Electrical Engineer and Consultant
By David Zierler, Director of the Caltech Heritage Project
December 8, 15, , 2021
DAVID ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It is Wednesday, December 8th, 2021. I am delighted to be here with Alan Cocconi. Alan, great to be with you. Thank you for joining me today.
ALAN COCCONI: Thank you for showing some interest. I'm here to help.
ZIERLER: Alan, to start, would you tell me please your current or most recent title and institutional affiliation?
COCCONI: None. I'm semi-retired, doing occasional consulting work or developing products on my own.
ZIERLER: What kind of consulting work are you doing right now, and for what industries?
COCCONI: Right now, I have no active projects for any customers. I'm actually doing stuff that interests me in terms of software for signal analysis and electronic instrumentation. That's what I'm spending my time on.
ZIERLER: How long have you been retired from full-time work?
COCCONI: Probably ever since I left AC Propulsion in about 2001, I've been not really doing full-time work, just doing various projects that interest me, often without a paying customer, but sometimes with one. I actually had a major health scare around that time which caused me to reevaluate what I wanted to do. That's kind of what led me to starting to do the solar UAV project.
ZIERLER: When did the solar UAV project get started?
COCCONI: Around 2001 or so. It led to the 2005 48-hour flight, which is the world's first UAV to do that on solar power. That took a lot of my time. As a spinoff of that, lithium batteries for electric cars came out of that work. Some of these projects initially seemed pretty useless, but they ended up creating various spinoffs that were useful.
ZIERLER: I'd like to ask some general questions about electric vehicles in historical perspective. Just to get a sense of how far back you go, what is your earliest memory of thinking about electrifying vehicles, developing alternatives to gas-powered automobiles?
COCCONI: When Alec Brooks and the others at AeroVironment suggested that I work with them on the Sunraycer project. That was my first involvement with electric vehicles at all.
ZIERLER: The Sunraycer project of course was solar-powered. What is your understanding of the intellectual trajectory or jump from solar-powered to battery-powered automobiles?
COCCONI: Having worked on the Sunraycer, it was clear that solar-powered vehicles were unlikely to be practical for everyday use. That car was an extreme vehicle meant for that purpose. It was a car that was the size of a large station wagon and weighed 300 pounds, and it could carry one person. It wasn't terribly practical. It was clear then that solar power was not really the answer, but the electric propulsion certainly had possibility. That project was kind of my introduction to electric vehicles.
ZIERLER: Today, of course, driving around Pasadena, Teslas are probably the most common car that you'll see on the road, at least here in this part of Southern California. When did you start to see electric vehicles becoming a viable contender, not just technologically, but as a matter of market share, in the industry?
COCCONI: The EV1 project showed that it could be done. Unfortunately, nothing happened right then in terms of manufacturing on any significant scale. But intellectually it was obvious after the EV1 project, or the Impact as it was called at the time, that this was all possible. It was just the question of the will to do it. As soon as the lithium batteries came in the picture in the early 2000s, from the laptop industry, then it became even more clear that this could be really a very viable solution and could meet most people's needs for transportation.
ZIERLER: Given the viability of EV1, are you surprised that right now in 2021, electric vehicles remain a niche market overall?
COCCONI: No, I know how reluctant the industry is to embrace any change. It took a company like Tesla that wasn't part of the original industry to force a change and it's why they have 80% or so of the market right now, because they were willing to embrace something new and different, while the others were in many ways fighting against it.
ZIERLER: What is your understanding of how Elon Musk drew inspiration from AC Propulsion?
COCCONI: He's not the one who started Tesla. It was Martin Eberhard who started Tesla. Elon Musk, in my opinion, his main skill is getting other people's money. He does that very well, so that enabled him to scale up and create what is now known as Tesla. But I don't think he had vision other than recognizing that the technology was available, and Martin Eberhard had started doing the Tesla Roadster on his own, with his efforts, but didn't have the financial resources to take it to the level that was required. That's where Elon Musk came in. I don't give Elon Musk a whole lot of credit for technological insight other than recognizing viable technologies when he sees them.
ZIERLER: What do you see as some of the key technological and infrastructural challenges to make EVs the dominant way of getting around in automobiles?
COCCONI: I think the technology is there. What's lacking most now in the industry, including Tesla, is good vehicle design. They've got good components, but many of the vehicles fall far short of what is possible with current technology.
ZIERLER: What do you have in mind? What does good vehicle design look like?
COCCONI: The vehicles currently that all the auto makers are making tend to be, in my opinion, much too heavy and too inefficient. With more careful design, you could get a lot more range out of the same battery and less energy used per mile, with probably 30% improvements easily available.
ZIERLER: What about safety considerations, the idea that a heavier automobile is a safer automobile?
COCCONI: I think that's a nonsense argument. If we all drive big rig trucks, then obviously everyone is equally unsafe, and we flatten pedestrians much more quickly, so I don't think that's a viable argument. In terms of global warming, the important thing is to use less energy to get where you're going. The only way to do that is with a lighter vehicle. With modern design techniques, the light vehicle can be made quite safe. In fact, the big, heavy SUVs have a worse safety record in terms of passenger deaths per mile driven than the smaller cars, if you look at the actual records.
ZIERLER: That gets me to a very important point, and that is getting a sense of your overall motivation. Where, for you, is it about bigger, faster, stronger? And where is it about—?
COCCONI: No, it's not bigger, faster, stronger. I'm kind of guilty for pushing the performance aspect of electric vehicles but that was a gimmick at the time. I didn't expect to be taken so seriously. I think it's the wrong thing. Right now, everybody is pushing for these fantastic acceleration times in electric cars and super high top speeds, and all this stuff that's totally unnecessary and counterproductive. It's not what's needed. What's needed is a car with reasonable performance and the cost-effective use of resources, meaning a smaller battery for longer range, fast recharging. A smaller battery is easier to charge quickly. You need lower-power infrastructure to do it. The impact on the world's resources are reduced if you go with that approach. Everybody talks about the environmental impacts of the lithium mining and all those other aspects, and if you build electric Hummers like GM is proposing, that's about the worst thing you can do with this technology.
ZIERLER: For you, the motivation is really about careful use of the world's resources.
ZIERLER: Is that to say that all of these YouTube videos about the Tesla Model S beating Lamborghinis and things like that, that's all nonsense and counterproductive?
COCCONI: I think it's all nonsense, and by now it's getting old. Any idiot engineer can make a car that's fast. That's not difficult to do. The difficult thing is to make a car that's efficient.
ZIERLER: What do you see as the next generation beyond lithium ion?
COCCONI: I'm not a battery chemist. I more or less observe what comes out. So far, there's some talk about the various variations of lithium with solid state batteries, etc., which show some promise. But in fact, the lithium-ion batteries are kind of good enough for what you need. They're not the stumbling block right now. Making a vehicle that needs less of these raw materials are the most important thing. I think what's lagging the most is the vehicle design. There are new cars coming out from Volkswagen to GM to Tesla, and they all strike me as very poor vehicle design.
ZIERLER: Given that big automobile companies are investing heavily in EV nowadays, what role do you see, if at all, for startups in the 21st century?
COCCONI: Less. AC Propulsion played a major role because nobody else was doing that work. Now it's kind of beyond that stage. That's one of the reasons I left AC Propulsion and sold off the company, because I saw that the role of the small player had kind of come and gone, to a large extent. Now you have to have enormous manufacturing capability to do anything in the industry.
ZIERLER: Given that you're critical of some of the designs coming out of the big automakers, best-case scenario, what do you want to see coming off the production line?
COCCONI: I want to see efficient, practical cars that can replace the vast majority of people's daily transportation with something that is less resource intensive. Vehicles have been evolving to be larger and heavier every year, over the last few decades. That trend needs to change if we're going to address some of these global environmental issues.
ZIERLER: When did you really, in your own intellectual development, become sensitive to environmental issues? How far back does that go?
COCCONI: Ever since the beginning of my electric vehicle work. I guess I've always been active outdoors and enjoyed cycling and hiking and always resented the smog and various other pollution aspects. The global warming stuff at the time wasn't a big issue and really I wasn't that aware of it. Certainly, in the last ten or 15 years, the global warming aspect has become a major one.
ZIERLER: Are you old enough to remember smog in Pasadena, or was that cleared up?
COCCONI: Yes, I remember not being able to breathe and having to use an inhaler to use my bicycle. That, I remember.
ZIERLER: You directly connected this to automobile emissions?
COCCONI: Yes. And it was connected, in fact. When the catalytic converters cleaned up the air substantially, it got a lot better.
ZIERLER: What role do you see in terms of emissions overall as EVs become more and more common?
COCCONI: I think it will help emissions. There are still other issues, like now heavy-duty vehicles are responsible for a large part of the emissions, and they are only now beginning to make more strong emission controls on those. That will help a lot as well. But in terms of CO2 emissions—there are other pollutants—electric vehicles certainly help. The transition to renewables for the electricity grid ties in well with the switch to EV.
ZIERLER: You mentioned bigger vehicles. Do you see semis, big rigs, becoming electrified? Do you think that's a viable technology?
COCCONI: I think it's viable for in-town deliveries where they don't drive long distances. I don't think it's yet viable for long cross-country hauls.
ZIERLER: Why is that?
COCCONI: Because the energy requirements are much higher, and the recharge infrastructure to charge big trucks at a rapid rate will be very expensive. As usual, with the new technology, do what works best first. Don't try to do the impossible stuff. What could work very well is for all the tractor trailers that do the deliveries in town and coalesce the cargo to the main warehouses, they could certainly switch to electric. They don't drive that many miles anyway. For he people who drive 1,000 miles a day, the electric still isn't that competitive economically with other things.
ZIERLER: Just out of curiosity, what do you drive?
COCCONI: Right now, I drive a Hyundai Kona, electric. I chose Hyundai because I really—Elon Musk has been a very distasteful person in my opinion. My interactions with him were not pleasant, and I have not enjoyed his various sort of communications [laughs] to the world. Also, Teslas are too luxurious for my appeal, and a Hyundai Kona is a more efficient vehicle. It's actually lighter and slightly more efficient than the Model 3.
ZIERLER: The Hyundai sounds like it's a little closer to your ideal of a more reasonable—
COCCONI: It's still not great, and the ironic thing is that the Hyundai is a conversion from a production gas vehicle. It's not a purpose-designed electric. Almost by accident, Hyundai did a pretty good job.
ZIERLER: Can you explain a little bit of the engineering, why it's so much better to have a purpose-built electric car from the get-go?
COCCONI: It could be much better if your intentions are good, but showing that Hyundai can pretty much do a very good job with a gasoline conversion shows how bad the purpose-built ones are.
ZIERLER: What about the Chevy Bolt? What are your feelings about the Bolt?
COCCONI: It's an okay car, again not a great chassis. It's reasonable. They messed up on their battery with various issues. Hyundai has some of the same issues, but not quite as bad. They've had to do some recalls which is unfortunate. It doesn't help for the PR. But the vehicle is okay. It's kind of not a very spectacular vehicle in any dimension, on the other hand it's quite practical and the costs are okay, so it has been a good steppingstone and I wish they'd learn from it and do something better. Now they're concentrating on these pickup trucks and Humvees, which is ridiculous.
ZIERLER: Are there any EVs coming to market that you're excited about, or at least demonstrate a step in the right direction?
COCCONI: No, none that I'm currently aware of. I look at my Hyundai from about two years ago, and I don't see anything I like better.
ZIERLER: That's interesting.
COCCONI: In fact, the new Hyundai, which is purpose-built, is less in the direction I like. It's got some interesting technology for faster recharge and some other things in the power electronics, which if put in a good car would be nice. But the new Hyundai sort of emulates a Tesla Model S.
ZIERLER: To give a sense of all of this in context, let's take it all the way back to the beginning. Let's start first with your parents. Tell me a little bit about them.
COCCONI: They were both nuclear physicists, and they were working CERN in Geneva, Switzerland, as I grew up, and that's where I grew up. I was brought up in a house that discussed science often. They were also avid mountaineers on the weekends. They loved going to the mountains and hiking and skiing.
ZIERLER: Where did your parents grow up?
COCCONI: They were Italian. They both grew up in Italy, and they worked at Cornell for 15 years. I'm an American citizen; I was born while they were at Cornell.
ZIERLER: Did you understand how pathbreaking it was for your mom to be a nuclear physicist?
COCCONI: Yeah, she talked about that quite a bit, and she was one of the few. Of her generation, just about all the female nuclear physicists were Italian, which was interesting. [laughs]
ZIERLER: Did you speak to your parents more in Italian or in English?
COCCONI: Some of each. They spoke to me in Italian, and I responded in English was often the pattern, but some of each.
ZIERLER: Where did you grow up? What years were you in Europe and what years were you in the United States?
COCCONI: I left the U.S. when I was four years old, so it's not very significant in my education or anything. From four to 18, I was living in Switzerland.
ZIERLER: Now, it's interesting; I don't detect any accent at all. What might explain that?
COCCONI: I went to an English-speaking school. I went to the International School of Geneva, where I was surrounded by other English speakers, so my English was developed there. I spoke French as well, and I still do. That was my upbringing. I took the International Baccalaureate program in high school and then applied to Caltech and came to California.
ZIERLER: Did your parents involve you in their work at all? Did you have a good sense of what physicists did for a living?
COCCONI: Some. I was never really into the nuclear physics, quantum mechanics-type stuff that they were, so that was less my interest. It was always more engineering and hands-on oriented, than the more theoretical aspect of what they were doing, even though they were experimental physicists. But no, I went in with my parents to work once in a while, looked around, and enjoyed seeing all the technology used in their work. That was always interesting for me.
ZIERLER: Now did you consider schools both in Europe and the U.S., or you specifically wanted to come to the U.S.?
COCCONI: I applied to Cambridge in England. I didn't get in. Several universities in the U.S. accepted me, and I ended up going to Caltech.
ZIERLER: Why Caltech?
COCCONI: I guess because my parents encouraged me to, which I'm not sure was the best choice in the end. I had a very difficult time at Caltech. I was not happy there.
ZIERLER: Tell me about that. What were some of your challenges?
COCCONI: It was a very non-social atmosphere and very intense, and I had an advisor who was very unhelpful. I probably should have switched advisors. Other students told me I should in my freshman year, but I didn't listen to them. Afterwards, it was kind of too late to do it. I struggled academically at Caltech and found that the instruction was really aimed—each department taught as if you were going to specialize in that department. As an engineer, I had a lot of trouble with the math instruction being oriented to math majors, not to engineers. I felt that hurt me overall.
ZIERLER: What was your major at Caltech?
COCCONI: Engineering and applied science, mainly electronics.
ZIERLER: Did you have any laboratory work that was helpful for you?
COCCONI: Yeah, the electronics stuff was fine, and I worked with Dr. Middlebrook and Dr. Ćuk in power electronics quite a bit, and I took their courses. Those, I thoroughly enjoyed, and that's the area I went into. Some things at Caltech were great, like access to machine shops and equipment to do whatever interested you as a student. I took advantage of that. That was great at Caltech. The actual way the courses were taught and the academic environment I found was incredibly brutal.
ZIERLER: Were you a tinkerer? Did you spend as much time as you could in shop making stuff?
COCCONI: I did, and that probably hurt me academically some.
ZIERLER: As you said earlier, even back then you were sensitive to the idea that smog was a real problem and that there could be solutions in electric vehicles.
COCCONI: No, I was not.
ZIERLER: That's too early?
COCCONI: Nope, I was not involved in that at all. My only interest then was getting a career that was not military, because I didn't want to contribute to the military effort anywhere in the world. That was my concern. In fact, when I first went to Caltech, I thought I'd do aeronautics, and then I realized that it was impossible to do a non-military career in aeronautics, so I kind of switched to electronics, thinking it would be more versatile.
ZIERLER: At what point did you decide to stay on, even if only briefly, as a grad student at Caltech?
COCCONI: Again, I was involved with the power electronics group run by Drs. Middlebrook and Ćuk, and their work was interesting, and I was doing well there. After graduation, they offered me a full scholarship for a graduate program.
ZIERLER: Why ultimately did you not stay in the program?
COCCONI: Because I was too burned out academically and realized that I wasn't doing well, and I would be happier outside of Caltech.
ZIERLER: Did you have a sense that you wanted to stay in Southern California, or did you think about returning to Europe?
COCCONI: Not being a Swiss citizen, it would have been difficult to return to Europe. I had no rights there, since my parents were there under diplomatic status. The way it works is that even though I grew up there, I couldn't just move back.
ZIERLER: What opportunities were available to you?
COCCONI: In the U.S., basically what happened is when I left Caltech, I worked for a company created by the same two professors who were running the power electronics department at Caltech. I worked for their company for two years. To me, it was a very easy transition. It was offered to me, and I got to do work outside of academics, in an area I liked, and I did well there. That was kind of the start of my career, was the two years I spent at TESLAco.
ZIERLER: TESLAco, of course, there's no relation to Tesla, but is there—
COCCONI: No, not at all, other than everybody involved in Power electronics likes the name Tesla.
ZIERLER: I see, so it still goes back to Nikola Tesla.
COCCONI: It goes back to Nikola Tesla, but that's it. It's just a fascination with the character.
ZIERLER: Tell me about TESLAco. How did it get started? At what point did you join?
COCCONI: TESLAco, it had just been founded by the two professors, to get some research and R&D contracts for power electronics development, using some of the technology that had been developed at Caltech. It was a small company of three or four people, just doing power electronics R&D.
ZIERLER: I wonder if you can explain—the words seem like they would make sense, but if you can explain, what exactly is the field of power electronics?
COCCONI: Using electronics to process power, meaning you're not processing information, but you're taking power in one form, for example from a solar panel, and converting it to another form, which is AC power to run your house. That's an example of power electronics. The little bricks that run your laptop are also an example of power electronics, because they take the AC from the power line and convert it to power your laptop needs. Which sounds trivial, but if you look at the details, there's actually a lot of quite sophisticated engineering in there to make these things compact and efficient and quiet and everything else.
ZIERLER: What was the mission or what were some of the imagined clients of TESLAco?
COCCONI: They were doing various custom power supplies for various companies that needed them for their product. One of the major contracts I worked on there was from Sandia National Labs. They were giving out contracts to develop photovoltaic converters for rooftop solar installation. I developed an initial unit for that application under their contract. That's where I learned a lot of the techniques of higher-power electronics that served me well later.
ZIERLER: Was this the very early beginnings of the adoption of rooftop solar panels in California?
COCCONI: Yes, it was the very beginning of it, and there were research contracts available to develop electronics to support that industry.
ZIERLER: I wonder if you see a similar historical trajectory to the EV1, where there was something viable, but it was not adopted nearly early enough.
COCCONI: I think the solar probably had a smoother time. It was gradually adopted. Even then, there were various installations being put in place. Well, the EV1, kind of everything died completely after that project ended. The solar was more of a continuum. The solar panels were still relatively expensive at the time, so they weren't that cost-competitive with other energy sources. It really took the cost of the silicon panels to come down substantially to make the final explosive growth we've seen in the last years.
ZIERLER: When you left TESLAco in 1983, was the company still viable?
COCCONI: Yes, it was viable, but I had developed an interest in doing UAV work. I didn't have any customers, but I—
ZIERLER: What are UAVs, Alan?
COCCONI: Unmanned air vehicles. Remotely operated aircraft with video links and telemetry links and the capability of flying many miles from the control site.
ZIERLER: How did you get involved or interested initially in UAVs?
COCCONI: I had always been a model airplane nut my whole life, ever since I was ten years old. As I learned electronics, it was a logical progression to apply the electronics to the model airplane. At the time, video cameras were just becoming available and all that, the smaller ones. I realized it would be kind of fun to start playing with this stuff. I met somebody, a friend of mine, who was doing some of the stuff actually for the military industry who became involved in the Predator project later, what became the Predator UAV. But I knew him before he ever worked on that. Seeing the work that he was doing inspired me that it would just be a fun area to get involved in and develop some hardware and learn how to make all these systems. I basically quit my job and lived off savings for over a year working on developing these aircraft. I spent a lot of time doing it.
ZIERLER: Given your sensitivity as an undergraduate to not working or being involved in the military industry, did you recognize the obvious military potential of UAVs? Was that something you were concerned about?
COCCONI: Yes, I did, but I was hoping to find some commercial applications. I didn't have a customer, so at some point, I was just doing it on my own, for my own interest. Eventually, Dale Reed at Edwards Air Force Base—who wasn't actually involved in military stuff; he was involved in basic aero research stuff—was made aware of my work, and he ordered one of my complete systems.
ZIERLER: Were you essentially working out of your garage? Did you have any startup money to help you out?
COCCONI: No, I had no startup money at all. I was working in my apartment in Pasadena, initially, and then I bought a house out here in Glendora, which is still the house I live in. I started doing UAV work out of a rented apartment in Pasadena, and then continued when I bought a house in Glendora, when I was doing some simultaneous consulting work for MK Products doing welding power supplies that allowed me to buy the house. I had some paying work doing power supply work for MK Products and doing UAV work at the same time. The Edwards project came along about that time.
ZIERLER: What were some of the materials you considered as you were developing UAV prototypes?
COCCONI: At the time, I was doing everything out of fiberglass, because carbon fiber wasn't yet very affordable. It was fiberglass, epoxy, and all the electronics to make the things work, and developing autopilot systems, et cetera, for the UAVs. That was what I was working with, and I was building everything from scratch. I wasn't buying existing components, because first of all, there was hardly anything on the market then. Not like now, where there are all sorts of people selling UAV components. Back then, there was nothing. It was scratch, building everything from tracking antenna systems to the controls and instrumentation, etc. That was a good education.
ZIERLER: What did you learn about yourself as a salesman or a self-promoter as you were trying to get people aware of what you were doing?
COCCONI: I wasn't very good at that. In fact, the UAV work never really paid for itself, but it was interesting intellectually, and that didn't really bother me much.
ZIERLER: How did you capture NASA's attention for this?
COCCONI: Oh, just introductions through friends.
ZIERLER: What would NASA have done with a UAV?
COCCONI: I never really went to them directly. It was somebody told them about the work I did, and then they contacted me.
ZIERLER: What was NASA's interest in UAVs? What were some potential applications?
COCCONI: They were using them to do various tests of aerodynamic configurations for various—just exploring different ways of designing aircraft and being able to test initial concepts unmanned was useful to them. They wanted to develop that technology.
ZIERLER: Tell me about some of your consulting work for MK Products during this time.
COCCONI: That was my first major consulting project on my own after leaving TESLAco. I think they called Caltech asking if they knew any students that wanted to do consulting and somehow, they got my name through the department secretary, I believe. That's how I got that contact. They were a welding company making all kinds of welding equipment, and they wanted to develop a new high-tech power supply for their welders. I worked with them for two years or maybe slightly more, overall, to develop what became the MK-2000, which was a 15-kilowatt portable welder. Quite innovative at the time.
ZIERLER: What are some of the considerations for coming up with power supplies for welding equipment?
COCCONI: At the time, it was the highest power project I had ever done, with 15 kilowatts or so. It was learning how to handle high-power stuff and do it in a way that was controlled, and setting up all the equipment to test and develop the circuits. It was quite a job, and MK Products was willing to support it. They had hired somebody previously to try and do it who had had very little success, so I was their second consultant on the project, and ended up basically starting from scratch. But I was successful and made a product that worked for them for many years.
ZIERLER: Did you specifically want to remain a consultant? Did you ever think about going in-house for any of your clients?
COCCONI: I guess as a student at Caltech, I got a two-year scholarship from GM, where I worked as an intern at GM Research Labs. That kind of taught me I really never wanted to work for a large corporation. I didn't fit in very well. It wasn't my character. Getting consulting jobs was attractive, and when it started to work out, I said, "Well, fine, I'll continue with that."
ZIERLER: Financially, you found that it was stable? You were able to make ends meet?
COCCONI: Yeah, consulting worked well, and it was fine. Again, I've always lived in a pretty simple manner, so I didn't have enormous financial aspirations. As long as I could make enough to keep on doing the other side projects I wanted to do, I was happy.
ZIERLER: Alan, how did you first get involved with AeroVironment?
COCCONI: When I developed the UAV system, I contacted Alec Brooks because I knew he was at AeroVironment. I knew they were doing various aircraft projects. I set up to go over there and gave a presentation showing the hardware I developed and the systems I had developed and told them if they ever had any non-military contracts, I'd be happy to work with them.
ZIERLER: Did you know Alec from Caltech?
COCCONI: I knew him from Caltech, yeah. We both used the same student machine shops. He was a couple years ahead of me, but I knew him through the various on-campus facilities available for students. He was building human-powered vehicles at the time in the student machine shop. I was building model helicopters.
ZIERLER: Where was AeroVironment at that point? How developed were they?
COCCONI: They were in Monrovia. They had done some of the human-powered aircraft and some solar powered, the one that flew across the English Channel or did the first human-powered aircraft with Paul MacCready. I knew they were involved in various aircraft projects which were interesting.
ZIERLER: What about some of their work with cars?
COCCONI: I don't think they had done anything with cars before that, that I was aware of.
ZIERLER: Sunraycer was still on the horizon at this point?
COCCONI: Yeah, and AeroVironment had no experience with cars at that time, as far as I know.
ZIERLER: Alan, what was your first project with AeroVironment in 1986?
COCCONI: It was the pterodactyl.
ZIERLER: Tell me about that. That's a wonderful story. How did that get started?
COCCONI: I wasn't involved at all in the start of that. I read about AeroVironment getting the contract in the L.A. Times, and I remember reading about it and thinking, "Oh, I guess they might be calling me, because that kind of falls into the category that I discussed with them." I remember making that comment to my girlfriend at the time, and she kind of laughed at me. "What do you mean, you read an article in the L.A. Times and you think they're going to call you?" But they did. [laughs] That's how I got involved, because then actually a lot of the technology I had developed for the UAVs went into the pterodactyl.
ZIERLER: What was the project, making a flying replica of a pterodactyl? What was this for?
COCCONI: It was an 18-foot wingspan flying bird with flapping wings and various stability augmentation systems to make it work without a tail and a big head upfront. It wasn't all that different from the UAVs I had done. It had some different specific requirements and a very ungainly air frame to work with, but we did our best to make it work for the film.
ZIERLER: Tell me about the film. What was it about?
COCCONI: The film was on the history of flight. It was the usual IMAX thing with lots of visuals and not a whole lot of storyline. But it started out with the evolution of animal flight and then showed man starting to make the first aircraft, with the Wright brothers onwards, and then disclosed that some of the animal flight video made at the beginning was actually the replica bird, so it was kind of trying to make the full circle between manmade and natural flight.
ZIERLER: What were some of the key engineering challenges in this project?
COCCONI: Getting a very unstable air frame to fly straight. [laughs] Birds have a brain and quick reflexes. We'll call it a bird; well, it kind of was. It was a dinosaur, which is a bird. But it was an air frame that didn't want to fly straight on its own and had to have all sorts of active controls to keep it pointing straight ahead. It was a challenge to get all those controls to work in a manner that was barely enough to make it fly straight for the film. We never got it to flap hard enough to climb because when we did that, it became unstable. They cheated a bit with the cameras, and made it look like it was flapping and climbing, but it was actually flapping and gliding.
ZIERLER: Did you work directly with Alec on this?
COCCONI: Yeah, I worked with Alec and the others on the team. I developed the electronics in my shop and went over there and spent a lot of time in Monrovia integrating the whole thing and working on the whole project, and I was involved the flight tests. So yeah, I worked with him quite a bit.
ZIERLER: The idea, as you said before, that your experience with GM convinced you that you didn't want to work with a large corporation, what about AeroVironment? Did you ever think about solidifying your relationship, not just being a consultant but being an employee of AeroVironment?
COCCONI: No, that had no appeal to me. I wanted to maintain my independence.
ZIERLER: Were you doing things on your own during these years as well?
COCCONI: I was continuing my own UAV stuff for fun, and I liked the freedom of being a consultant, being able to absolutely choose what projects I worked on. I knew if I was an employee, I'd have much less freedom. I was better working in my own shop. In some ways, it was better equipped than what AeroVironment had for what I wanted to do. It was more comfortable for me to work at home and interact with them when needed.
ZIERLER: As you say, it was all in your home shop. You never developed a commercial space of your own?
COCCONI: No, I didn't. it was always my home shop.
ZIERLER: Were you there right at the beginning when AeroVironment got involved with the Sunraycer project?
COCCONI: It took Alec a bit of effort to convince me to do a car. I wasn't all that enthusiastic of doing a car. I was more interested in airplane stuff at the time. I remember when he approached me about getting involved in the Sunraycer, it took a few meetings and some good talking up by Alec and others to get me to come on board. But eventually I did, and then I realized it was an interesting project and was fun to do. There, my experience with the photovoltaic converters I had done for Sandia Labs was actually very useful for the Sunraycer. I used some of the same concepts there and developed on them.
ZIERLER: What ultimately convinced you to join the Sunraycer project?
COCCONI: Just the technology was interesting. I realized that I had the right background to be useful and possibly do quite a good job.
ZIERLER: At this point, I know it's still early on, but intellectually, when you start working on Sunraycer, is that the point when you start thinking about electrifying vehicles?
COCCONI: Some. The Sunraycer was so intense. We had eight months from the start of the project to having to win the race. There wasn't a whole lot of time for thinking about much else. [laughs]
ZIERLER: Did you have any interface directly with GM and their support of the Sunraycer project?
COCCONI: Yes, I did. In fact, I did trips to GM, to the same research lab where I worked as an intern, in support of the Sunraycer project. So yeah, I went back and forth with AeroVironment and interfaced with GM as needed. I went to Australia for the race and was part of the whole support team.
ZIERLER: Do you have a sense of why it was GM that was so intently interested in this technology? Like where is Ford and Chrysler in all of this?
COCCONI: Ford had an entry, also, in the Sunraycer. So, they were there, and I think Mitsubishi did, various automakers did have entries. I wasn't aware, at the time, of what marketing efforts AeroVironment did to GM to get that contract, or what contacts they used. But they did that work; I did not. Somehow, they secured the contract from GM and called me after the fact.
ZIERLER: As a team exercise, what was your area of expertise? What did you contribute to the development of the Sunraycer?
COCCONI: All the power electronics, everything from the battery to the motor, and from the solar panels to the battery. All the electronics that controlled those functions and executed those functions, I did. The motor itself was developed by GM, by a GM research lab, and I did all the electronics that made it work.
ZIERLER: I wonder if you can talk a little bit about some of the engineering options, about having a battery versus direct power from the solar panels, right to the motor.
COCCONI: Having a battery was an assumed condition. It was not anything we innovated. It's obvious with a solar-powered car that you need to be able to have spurts of power beyond what the solar panel can do, and you need to have a battery to manage that. Also the way the race was set up, you obviously needed a battery, because morning and evening, there were a few hours where you were allowed to charge with the car stationary and replenish the battery, and then you could drive at other times of the day. The energy storage of the battery was kind of a given with conditions we were presented with.
ZIERLER: In terms of the energy capacity of the solar panels, how much was known from previous applications of solar panels, and how much were you figuring out in real time because this was a brand-new application?
COCCONI: It was a new application but solar panels were already well established. AeroVironment did the systems optimization work. Since it was a GM project, they teamed up with Hughes Aircraft in the satellite division, who were very used to making solar panels, and high-grade ones. Hughes Aircraft actually built the solar panel for the Sunraycer. AeroVironment built the Kevlar and fiberglass structure that supported it, but then they shipped that to Hughes Aircraft to put the solar cells on it. We used space-grade silicon solar cells, which were the best available at the time. It's a bit of a funny story how we ended up with a gallium arsenide panel.
ZIERLER: Tell me about that. How did the gallium arsenide panel come about?
COCCONI: Initially, it was a silicon panel with the best space-grade silicon cells you could buy, which ended up being a few hundred thousand dollars for the panel, I think, by the time it was all built and all the labor that went into it. It was a relatively expensive panel with quite good performance, what was available at the time. Those cells were like 16% efficient. I think it was two or three months before the race, I was at a meeting with Hughes, and we had already built the second car, to have spares to take with us to the race. We had two cars and one solar panel, because the solar panel was deemed expensive, and the second car, once we had built one, it wasn't that hard to make another one.
I was at a meeting at Hughes Aircraft, and I mentioned, "Well, since we have the second car and no solar panel for it, if something bad happens in the race, like we have a rollover or accident or something or a tree falls on the car and wrecks the solar panel, we're stuck." I suggested we get commercial-grade solar cells and make an inferior panel for the backup car, just to have something in case a disaster happened. At the meeting, they said, "Yeah, that's quite a sensible idea. Maybe we should consider it." What happened is that then subsequently they had internal meetings at Hughes Aircraft, and the cheap, commercial-grade panel morphed into an experimental extremely expensive gallium arsenide panel, because they realized, well, since this one, we don't have to be sure it will work great, we can try something new and experimental on it. They had never built such a large gallium arsenide panel and they realized, well, this would be an opportunity to get some experience doing it. They ended up spending I think more than a million dollars on the gallium arsenide panel.
ZIERLER: Were you aware of some of the Sunraycer's competitors, the technologies that they were pursuing, or were you really operating in a cocoon?
COCCONI: We were looking at what they were doing, and we had some concerns about how competitive we would be. That's one of the reasons that Hughes Aircraft decided to go out and do the gallium arsenide panel, to make sure we had more of an edge.
ZIERLER: Did you see all of GM's interests and investment as a mandate, really, that you had to win this race?
COCCONI: Yeah, it was clear that with this effort, we better win it. [laughs] That was very clear. Put a lot of pressure on me, because I was the only guy responsible for all the electronics that made the car move. We actually built five sets of spares. We had two cars, and five sets of spares for all the electronic components.
ZIERLER: I know this was such an intense project to work on. What was most fun for you during these eight months?
COCCONI: I can't say any one thing. It was all a very intense, challenging project. It was fun to be part of it, and having a real deadline made everything more rational in terms of all of the management decisions, that everything had to happen quickly.
ZIERLER: Did you go to Australia? Did you want to go to Australia?
COCCONI: Yeah, I wanted to go. I was the only one that knew how to support the electronics part, the propulsion electronics part of it, so I had to go. It was a fun trip. When we got there, we all got kind of scared about how big the support effort was. There were like 50 vehicles, 50 official GM vehicles following the Sunraycer down the Australian outback.
ZIERLER: Were you one of the drivers of the Sunraycer?
COCCONI: No, I was not. I didn't want that level of extra responsibility. I had enough already.
ZIERLER: Did you drive it just in testing mode? Did you know what it felt like on the inside?
COCCONI: Yeah, when testing on the test track in Arizona, quite a bit. I never drove it in a public road. Again, I stayed away from that level. The people who drove on the public roads were the ones who were going to be the drivers in Australia, and I did not want that role.
ZIERLER: I wonder if you could give a sense of what it feels like to operate the Sunraycer. If it's just at a standstill, what is it like to accelerate? How does that happen?
COCCONI: It was not that different from a modern EV. It was very smooth, gentle acceleration. That car was zero to 60 in about 22 seconds, I think. It was nothing spectacular. But I remember after the race, Road & Track did a road test of it just for entertainment and put it in their magazine, and they noted the acceleration time was about the same as the original Volkswagen minibus. [laughs]
ZIERLER: [laughs] That's great.
COCCONI: So it was slow, but it wasn't completely ridiculous. It was one-wheel drive, so it pulled a little bit to one side when you accelerated. But since the power is so low, it was quite manageable. It drove kind of like a big go-kart. It was extremely light with bicycle wheels and tires. But it drove okay. It was pretty pleasant to be in.
ZIERLER: When the race started, where were you physically, and what was the best position for you to be in, just to maintain control and awareness of what was going on with the electronics?
COCCONI: We were in an RV that followed the car down the road, from Darwin in northern Australia to Adelaide, where the race ended. We were in a chase vehicle with all the telemetry display computers. There was a whole telemetry system which I did not design. Another consultant from Caltech who I knew designed the telemetry system, John Gord, who was I think one year ahead of me at Caltech.
ZIERLER: What is a telemetry system, and how are you using it in this application?
COCCONI: It was monitoring the output from all of the different segments of the solar panels, looking at temperatures of the motor and electronics, battery stage of charge, et cetera. All that was sent to Macintosh PCs—they weren't laptops at the time; they were regular PCs—in the RV. There's a whole crew in the RV looking at the various conditions from the amount of sunlight, the stage of charge of the battery, to the course, telling the driver what to do to optimize the race.
ZIERLER: Maybe it's a silly question, but as long as you have sunlight, can a solar-powered car run continuously? There's no need to charge anything?
COCCONI: No, there's no need, but you have to adjust your speeds so you keep the battery reserved enough for a hill that may be coming ahead, or for the evening hours when you have less sun. There's a whole management strategy for how much of the sunlight goes to the wheels and how much goes to the battery at any given time.
ZIERLER: Coming off the starting line, what were some of the emotions running through you at that point?
COCCONI: Whether all my electronics would blow up in the first day and we wouldn't finish the race. That was my concern. [laughs] In the end, nothing failed at all. Everything worked. We didn't have to use any of the spares. So it all worked out very well. I remember when we were a fifth of the way through the race, I said, "Okay, if we maintain this failure rate, I'm okay, because we've got five sets of spares." [laughs]
ZIERLER: How far from the beginning of the race could you breathe a sigh of relief that you guys were going to win this?
COCCONI: I think by the end of the second day, it was obvious we were way ahead.
ZIERLER: What was the competition like? Did Sunraycer just blow everyone out of the water? Was it close for a little while there?
COCCONI: Initially, the first half day, it was close, because so many of the other teams didn't understand battery management at all and had very large batteries that they were depleting, so they could go fast for most of the first day. After that, they were in big trouble, and we were not. We had a very careful battery management strategy where everything went as planned.
ZIERLER: I wonder if you can explain that in some technical detail. What set the Sunraycer's battery management apart?
COCCONI: AeroVironment had a whole bunch of people who were very skilled at looking at missions and understanding how to optimize vehicles. They had done this for aircraft projects at various times, like their human-powered and solar-powered aircraft. They understood about energy management and strategy and operating procedures. In that department, they're very strong. In fact, they had I think two mathematicians who actually spent the whole time developing computer models of the race and the car, so they knew exactly how to optimize the performance.
ZIERLER: What was it like when you got to the finish line? Was there a huge celebration?
COCCONI: Yeah, with GM and 50 support cars, you can imagine they organized a pretty good celebration. [laughs]
ZIERLER: Tell me about it. What was the party like?
COCCONI: I don't know, we were all so tired. After five days of very little sleep going across in an RV, it was nice to have it be over! [laughs]
ZIERLER: What was your sense of GM's reaction to this at a strategic level? What did this tell them was possible that might not have been before the race began?
COCCONI: That they could get a lot of advertising out of a couple million dollars or so budget for a special event. That's what they really learned. I think they learned very little about electric vehicles. They never understood the technology that went into Sunraycer. They never made a big effort to understand it in any way. It was a big PR effort for them, and as a PR effort, it was very successful.
ZIERLER: When you returned from Australia, what did you do next? What was the next project to work on?
COCCONI: I didn't do any projects for a while until the Impact (which later became the EV1) came along.
ZIERLER: In that interim year, between 1987 and 1988, you were working on your own stuff again?
COCCONI: Yeah, I was just working on my own projects, I think quite a bit of the UAV stuff. I just continued on my own.
ZIERLER: Were you gaining more customers? Was the UAV market expanding at all?
COCCONI: No, I had no other customer, because even customer I had dealt with at NASA, I was not totally comfortable with, and I never had any other customers for UAVs.
ZIERLER: What about since with your Caltech connections, what about JPL? Was JPL aware of what you were doing? Was that relevant for any of their missions?
COCCONI: I had no contact with JPL. I didn't deal with them at all.
ZIERLER: Tell me about your involvement at the earliest stages of GM Impact EV project. How did that get started for you?
COCCONI: It got started basically when I was called to a meeting at AeroVironment to discuss my participation in such a project. Actually, Wally Rippel reminded me about some stuff about the meeting that I had forgotten. My recollection about that meeting is a little bit fuzzy. Wally has a better recollection of what I said than I do, which is kind of strange, but that's the way it ended up. Apparently they were discussing what kind of vehicle to present to GM, and I guess I made some comment that if it wasn't a vehicle with reasonable performance, I wouldn't be interested. I wasn't interested in like a milk delivery vehicle or something like that. That's not what I would be willing to work on. Apparently, I said that. I don't remember that firsthand. Wally has reminded me of that several times.
ZIERLER: Was your sense that the GM Impact project only got started or was possible because of Sunraycer? Do you see these things as sequential?
COCCONI: Yeah, they're sequential because AeroVironment had shown its expertise with the Sunraycer, that it could actually deliver a project with reasonable budget and good results in the EV field. When they proposed to GM to do the Impact, they had some credibility and they managed to get some attention of some people at GM and at Hughes Aircraft.
ZIERLER: Who did you see at GM as really driving the support for the Impact project?
COCCONI: I'm terrible at names. It was the guy at Hughes—his name, oh my god. I knew it yesterday and then all of a sudden it's escaping me. There was one engineer at Hughes Aircraft. I'm sure you've heard his name from Alec. (The name is Howard Wilson)
ZIERLER: Bob Stempel?
COCCONI: No, Bob Stempel was the president of GM at the time. No, it wasn't him. It was a Hughes Aircraft fellow. He wasn't a GM person. Sorry. I think at Hughes Aircraft, being more electronics-oriented, they recognized the value of an EV development program, and to help support AeroVironment's marketing to GM.
ZIERLER: What was the relationship between Hughes and GM at this point?
COCCONI: I think GM had just bought Hughes Aircraft, so Hughes Aircraft was kind of new to the idea of being a partner with GM, exploring what was possible.
ZIERLER: How would an aircraft company slot in on an automobile project?
COCCONI: Hughes Aircraft wasn't really an aircraft company. It was more of an electronics and satellite company. Aircraft is a bit of a misnomer for what they did. They were heavily into electronics for all their satellite missions, so that was an area of their expertise that GM really didn't have.
ZIERLER: Did you have to be convinced yet again by Alec to get involved, or you were interested at this point?
COCCONI: As soon as it became an interesting vehicle as far as I was concerned, and I saw it had some chance of developing some innovative technology that would be useful in the long term, I was interested. It didn't take much. The Sunraycer project had been fun. As soon as this coalesced and was something that was technologically viable and interesting, in my opinion, I was very happy to be on board.
ZIERLER: Even at this early stage, was the possibility that EVs would provide some solutions on emissions and resources, were you thinking about that?
COCCONI: Yeah, by then it was clear, and that's why we were suggesting it to GM, as a way of having a lower-pollution form of transportation and less energy-intensive, etc. There were various oil shortages at the time, so they were being discussed as the way to get transportation running on something other than oil.
ZIERLER: What about the decarbonization of the electric grid, the use of nuclear and wind and solar? Was that part of the beginnings of this, that an electrified grid would be good for electric vehicles?
COCCONI: The talking point back then is if you build electric vehicles, in a way it's a flexible energy source. You can adjust the way you generate electricity as needed for various environmental and economic concerns. We always promoted the electric vehicle as even though electricity might right then be mostly generated by coal, it didn't always have to be that way.
ZIERLER: At the earliest discussions of the Impact project, did you see it more as a novelty, or was GM really committed even then to transforming a concept car into something that could be mass produced?
COCCONI: No, they were not committed to that at all, and that was kind of forced upon them by California Air Resources Board, that I think the initial development team at AeroVironment kind of worked to create a political situation where GM couldn't back out.
ZIERLER: From a marketing perspective, wouldn't GM have wanted to do this because people were interested in the technology, that it would sell?
COCCONI: That's not the impression we got. [laughs] They wanted to do something similar to what they had done with the Sunraycer, to show how great they were and look at their wonderful engineering, even though it wasn't really theirs. But that's the image they wanted to convey with the Impact.
ZIERLER: When did you first meet Wally Rippel?
COCCONI: At Caltech in one of the machine shops.
ZIERLER: Had you remained connected with him? Were you in contact over the years?
COCCONI: On and off. For example, when I was at TESLAco doing the solar inverter for Sandia Labs, he was sent over by Sandia Labs from JPL to take a look at the project and give a report. I dealt with him a bit on that. He came over for a few of the meetings to be a senior person overlooking this development project.
ZIERLER: For you, what aspects of the Sunraycer project were transferable, and what had to be built from scratch for the Impact?
COCCONI: Some of the motor drive technology was similar, but it had to be scaled up tremendously. The Sunraycer was seven kilowatts, about ten horsepower, and we had to go up to 130 or so horsepower for the Impact. It was a big scale-up, and it was a little bit scary as an engineer to do such a big jump. I had never done anything at that power level before. I had to develop new techniques and learn how to do it. That's one of the reasons the Impact had two motors. It was less scary to build two motors half the size than one large one, in terms of the motor and the technology to support it.
ZIERLER: What were the charging options that you considered for the Impact?
COCCONI: On the Impact, we realized—I think Wally gave some input on that as well—that it was possible, once you built a motor control system, to use the same electronics to make a charger, with very few additional components. That's the route we went on the Impact. It had a built-in charger that could do 20 kw. With a lead acid battery at the time, it could do a full charge in one hour.
ZIERLER: How much range would that give you?
COCCONI: About 100 miles, if you drive gently.
ZIERLER: Were lithium-ion batteries viable at that point?
COCCONI: No, they didn't even really exist at any commercial level yet. Laptop computers weren't yet around, and nobody had lithium-ion batteries. It wasn't until around 2000 that laptop computers with lithium-ion batteries started to appear.
ZIERLER: What were some of the challenges in working with lead acid batteries?
COCCONI: They were way too heavy, and they were not very reliable, so when you put a whole bunch of them together, one would always deplete before the other and limit the whole pack. It was difficult to get lead acid batteries to operate properly in a large pack.
ZIERLER: I wonder if you can explain a little how a lead acid battery works.
COCCONI: Again, I'm not a chemist. I was always somebody just using them. But lead acid batteries in some senses are easier to deal with than lithium ions. You need less electronics around them to do a crude job, but they don't store very much energy, and they don't charge that efficiently. When you charge them up, you only get maybe 80% of the energy back out when you use them to propel the car. Not ideal in many ways, but it's all there was at the time. Most of the lead acid batteries in the world are designed for starting cars, not for energy storage for long-distance driving or long-term use. It was difficult to find batteries that were suitable. GM actually ended up developing their own battery for the EV1, their own lead acid battery, which was more tailored to a longer life, and deep cycling required for an electric car. They did a reasonable job. They worked quite well, within the limits of the technology. Towards the end of the EV1 program, they went to nickel-metal hydride batteries that had somewhat improved performance.
ZIERLER: Was anybody considering using solar panels on the Impact? Was that considered viable at all?
COCCONI: Not really, because on a normal car, you can only put a few hundred watts worth of solar panel on a car. Again, a real car, it takes 10,000 to 15,000 watts to go down the road, so it's almost insignificant what you can get from a solar panel on a car. You'd have to park for a week to get any significant extra mileage out of it.
ZIERLER: What were some of the considerations in terms of making a real car for everyday use? Did you use an existing chassis? Was everything built from scratch?
COCCONI: Everything was built from scratch. We tried to optimize the aerodynamics and weight because with lead acid batteries, you really couldn't make any mistakes and get a car that was at all useful. The Impact and the EV1 both were very well-optimized cars. A big effort went into the chassis design, and AeroVironment managed to overrule most of the stylists to end up with quite a rational design.
ZIERLER: What were some cues that you were taking from other automobile manufacturers in terms of aerodynamics?
COCCONI: Virtually none, because they were all doing it so badly. [laughs] We took cues from aircraft design, and we worked in the Caltech wind tunnel. All sorts of effort went in on AeroVironment's side to create a body shape that could be both somewhat practical and also quite efficient.
ZIERLER: Is this to say that even like a Porsche 911, that wasn't impressive aerodynamically to you?
COCCONI: No, it's not. It's absolutely not impressive. In fact, it was kind of a joke in the industry that at the time, the Porsche 928 was more streamlined going backwards rather than forwards.
ZIERLER: Interesting, interesting.
COCCONI: So, there wasn't a lot to learn from the existing cars. [laughs]
ZIERLER: What about materials for the body? What were some of the new materials that might have been available to you?
COCCONI: The original Impact was actually all fiberglass, to reduce tooling cost, but done in a way to simulate an eventual aluminum structure, which is what the EV1 was. That was all aluminum unibody, which GM was willing to experiment with, again to try and meet the weight targets and to get the final performance they wanted. We worked with fiberglass knowing it would be a simulation of aluminum.
ZIERLER: What about tires? Were there any unique considerations with tires and driving an electric car?
COCCONI: Again, you're biased more towards efficiency than road-holding or extreme performance of any kind. Again, we worked with various people at GM to select the best commercially available tires for that application. I think they might have eventually gotten some custom tires from Goodyear and some other auto makers to make small improvements. But yeah, obviously the characteristics you want for an electric car, especially when all you have is the lead acid battery, you have a tire that rolls as efficiently as possible.
ZIERLER: I'm very interested in the idea that this is going to be a car that can be designed for everyday use. What were some of the things that you and your team were sensitive to, in terms of making it attractive, making it fun to drive, making it easy to drive?
COCCONI: We saw from the Sunraycer that things like having one-pedal driving with the regenerative braking was a very nice driver interface, and we certainly put that into the Impact. We were probably one of the first ones to demonstrate that in a passenger vehicle, that you could do one-pedal controls with an electric car, which is kind of slowly becoming the norm. Just making a car that drives smoothly with no single speed gear reduction, no gear shift. Tried to do the best we could to take advantage of the new technology, over the relatively crude propulsion interface with an internal combustion engine.
ZIERLER: Was it a similarly high-pressure environment as the Sunraycer? What kind of time constraints were you working under?
COCCONI: Not as definite time constraints, so it wasn't this super high-pressure environment. We knew we had to get it done reasonably quickly, but it wasn't like an absolute race where if the car is not ready, you lose the race. It was a bit more relaxed, and we had some more time to do R&D more carefully to optimize various components. We spent a lot of time on the motor design and the electronics areas to get that right. AeroVironment spent a lot of time on the body and chassis design. They had help from GM engineers as well on the body design. Transformed the AeroVironment concepts into tooling that was amenable to an eventual aluminum fabrication. The suspension design was also in conjunction with General Motors suspension engineers, to get a design that was both aerodynamic and lightweight, which all the suspension components are hidden up inside the body, so the bottom could be streamlined. Various things like that were done quite carefully, working with AeroVironment kind of as the guiding force, and GM with some of the practical knowledge.
ZIERLER: Was money no object? What were some of the budgetary constraints in the development stage of the Impact?
COCCONI: My impression was the money was enough to do whatever we wanted. I wasn't really involved in the money discussions, but it seemed to never be an issue. On the other hand, AeroVironment does work pretty cheaply and efficiently, so it wasn't a huge effort. It was 20 people or so, working on the car, at AeroVironment.
ZIERLER: Given that you had the resources that you needed, what are some examples where you could really push the envelope in terms of the engineering, doing stuff at the best possible level, not necessarily with regard to belt-tightening?
COCCONI: I was kind of alone on the electronics, so whenever I needed materials or things fabricated, etc, it was never an issue. I could always just get it done. They didn't hire a team of five people like me to help me. That, they did not do. So I'm sure there were some constraints that AeroVironment had, but I really didn't see them as far as I was concerned. Whatever I suggested and was basically allowed.
ZIERLER: What about some of the regulatory challenges or considerations? Was there anything that you needed to take special concern of, to make these cars street-legal?
COCCONI: At the time, we were thinking about down the road we'd have to meet crash worthiness, etc. But obviously with a fiberglass car, it was not crash-worthy. It was just a mock-up of what the final design would be. But when they laid out how the various parts were designed, that was all I think looking forward to eventually having to meet all the various safety requirements. Obviously, some solutions that would have been grossly inappropriate were not allowed. The same with the electronics. There were some issues with charging, the way the charger was built, where we weren't quite meeting some of the requirements for plugging into outlets in terms of ground current, which I was working on to address. I was aware on the initial prototypes they weren't all the way there, but I was pursuing various efforts to make sure we could get there.
ZIERLER: From the very beginning to when you could actually drive the Impact around, what was the timeline? How long did that take?
COCCONI: I can't tell you exactly. I don't remember that precisely. In the order of two years or so. The first Impact couldn't be driven in the rain, because the air cooled, and the air came in from the front and went through the electronics in a way that wasn't safe if it was raining hard. That's an example of the shortcuts we took. We knew that eventually that could be solved, but we didn't want to deal with it. [laughs]
ZIERLER: Do you have a clear memory of driving it for the first time?
COCCONI: No one event stands out. I remember as soon as it started to be complete, we were driving it, and had some troubles with the electronics failing, and having to tow the car home, or limp home with only one motor running and not two, because there were some issues of failures, and we had to learn to make it more reliable. There were all sorts of problems when we first started driving it, and we were learning as we were going. Actually, the very first tests were not in the Impact body; we put everything in a GM van, all the same drive components, just to be able to drive it around, before the car was ready.
ZIERLER: As a matter of collaboration, tell me about working with Wally. What were your areas of expertise, what were his, and how did you work together with Wally?
COCCONI: His area was the motor design part, which I had very little experience with. He provided the basic starting point for the motor design. Then I was heavily involved in the testing of the motor, because to test the motor, you have to have electronics to run it. Together with Wally, we evolved the motor design to solve some minor issues and improve the performance. It was a collaborative effort with Wally on the motor, with him taking the initial lead on the design. He had done some work at JPL on similar motors, and so he had a good theoretical and practical understanding of that technology.
ZIERLER: How involved at the day-to-day level, the working level, were people from Hughes and GM? Were they giving advice? Were they telling you what to do? Or it was more detached than that?
COCCONI: Hughes had almost no input during the Impact program until the very end of it when we transferred the technology over to them after the car was fully demonstrated. The GM people in the chassis and suspension design had more input. The electronics side, Hughes Aircraft basically had no input.
ZIERLER: Did you see this, at that early stage, as something that would be widely adopted?
COCCONI: I was hoping it would be, but I saw the split personality of GM that was willing to fund this but really didn't want to adopt it. It was clear from the beginning that it was going to be an uphill battle.
ZIERLER: Is your sense that the various lobbyists that would have been aligned against mass production of EVs, do you see their influence right from the beginning?
COCCONI: I saw within GM management, there was reluctance to embrace the new technology. An example is when we were at the test track filming the promotional video for the auto show, when the Impact was first—fiberglass prototype was shown at the L.A. Auto Show—we had a license plate on the car that said, "The future is electric," which we thought was appropriate for a promotional video. But we were at the GM test track with their film crew, and the PR head came along and said, "That's too strong a statement. It has to go." They replaced it with a generic dealer license plate.
ZIERLER: Were you aware if Ford or Chrysler was paying attention?
COCCONI: Not directly. When GM started to show the car at auto shows around the world—they took it to Geneva, Switzerland, as well—we certainly saw other auto makers coming by and looking and noticing. I would say we had their attention to some degree, but what happened within those organizations, I don't have the detailed knowledge.
ZIERLER: What kind of press did the Impact get?
COCCONI: More than GM wanted. [laughs]
COCCONI: GM was happy to show it off but really didn't want to be committed to build anything. Then they ended up kind of realizing if they didn't build some sort of production vehicle, it would look very bad.
ZIERLER: Did you have an idea at the time that the Impact would lead to the EV1?
COCCONI: We were hoping it would, and that was the whole idea. That was the intent of the program, among the people who were working on it, but that was not really the intent of GM as an organization.
ZIERLER: Given all of these uphill battles, what is your understanding of how the EV1 came into being?
COCCONI: It came into being, again, with a mixed commitment. For example, they made sure not to sell them. They were all short-term leases, so they could stop the program at any time. It was clear they were very cautious, and they didn't want to commit resources long term.
ZIERLER: Were you involved in the EV1 at all?
COCCONI: No. I was involved to the point where I transferred all the technology I had worked on to Hughes Aircraft, and then I basically stepped back and was no longer involved. The effort from the Impact to the EV1, I was not directly involved in anything.
ZIERLER: As an outsider, I wonder if you can comment, what was different about the EV1 and what was straight adopted from the Impact concept?
COCCONI: The electronics considerably evolved. I did a lot of stuff with the analog electronics. That was my area. They went much more heavily in the digital direction, which is the thing to do, but it wasn't within my development capabilities at the time. They did a lot of changes that were needed for a production vehicle, which were appropriate. Some of the efficiency stuff, the drivetrain they didn't get quite right, but it wasn't too far off. They did some stuff pretty well. The chassis was pretty much faithful to the original concept. That, they stuck with.
ZIERLER: Did you have the opportunity to remain involved in the EV1?
COCCONI: Yes, if I had wanted to join GM or Hughes Aircraft, I probably could have, but I kind of felt my role was over. This became a thing with hundreds of engineers and this enormous project. I don't fit in very well in those environments, so I knew it was better to stay away.
ZIERLER: It's the same sensibility even from an undergraduate that you always wanted to remain on the outside as a consultant.
COCCONI: Yeah. I like doing the initial creative part of these projects and showing a concept that nobody has really done before. Then when it becomes a big corporate development effort, I tend to run away. [laughs]
ZIERLER: Last question for today, as a segue to the founding of AC Propulsion. Just for you, intellectually, scientifically, even politically with regard to your concern for the environment and resources, was the idea behind AC Propulsion a direct outgrowth from your work on Impact, or were there other things going into your motivations at that point?
COCCONI: No, it was a direct outgrowth, because I saw the way GM was going with the EV1 program and saw that technically they were doing some things in a direction I didn't agree with, for example their charging infrastructure and some other issues. I realized I had some ideas that could be developed in a significantly different direction to be quite viable. That's when I decided to start AC Propulsion. In fact, GM approached me when they heard of me starting to do my own electric car effort and offered to fund me as long as all the work I did would be owned by GM. I refused, because I was worried about getting into the same trap, where they could eventually make the final decisions of what went ahead and what didn't, so I turned them down. I started AC Propulsion with no external funding, just my own savings.
ZIERLER: Wow, that's great. Alan, that's a great place to pick up for next time, when we'll get to the beginning of AC Propulsion.
[End of recording]
ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It is Wednesday, December 15th, 2021. I am delighted to be back with Alan Cocconi. Alan, it's great to be with you again.
COCCONI: Thanks for having me.
ZIERLER: Today, I'd like to start with the origins of AC Propulsion. Take me back to the earliest conversations with Wally Rippel and others that ultimately led to the creation of this amazing company.
COCCONI: The start of it really came when I finished up with the EV1. I didn't like some of the directions GM was going, and I thought I had some ideas on how to do integrated charging and other things differently from how they were doing it.
ZIERLER: Let's go back right then and there. What was the problem that you saw with GM? What were the things where you wanted to take this in a different direction?
COCCONI: I didn't like their approach of the inductive charger, which ended up being a complete boondoggle, but that's the direction they went, with the paddle and the transformer in the paddle. That was a very expensive charging infrastructure. I didn't like that approach. The original Impact didn't have that. It had integrated charging. I really felt I had something to contribute in that area of how to do charging infrastructure. That kind of made me want to start my own effort. I also realized that GM wasn't terribly serious about electric vehicles, and I wanted to be able to do something independently to try to approach other automakers. In fact, working on my own, I got the first car running before AC Propulsion existed, working out of my home. I converted a Honda CRX with a completely new drivetrain, which at the time was 100 kilowatts, and had that operational before I started getting some interest in creating a company that could market the stuff. I had been talking to Wally and others throughout this period. Paul Carosa from Hughes Aircraft joined me, and basically the three of us—myself, Wally, and Paul Carosa—started the company.
ZIERLER: Why the Honda CRX? Of all the cars to do the prototype on, why this one?
COCCONI: Just because it was a relatively efficient lightweight car. It was one of the best cars available at the time for aerodynamics. It was front-wheel drive, easy to work with. Honda makes good vehicles. I just bought a new CRX and tore the motor out and put my stuff in it.
ZIERLER: What was GM's response? Were they paying attention to what you were doing? Did they try to co-opt this and bring it on board?
COCCONI: Yeah, they came to visit me and offered me financial support in exchange for exclusivity if everything I did was only for GM. I'm afraid I turned that down.
ZIERLER: Ford and Chrysler, were they paying attention as well?
COCCONI: Not at that time, no.
ZIERLER: Why ultimately did you not agree to GM's offer?
COCCONI: Because my whole reason for doing this was to get away from GM and the decisions they were making, so it made no sense to start another effort to be under GM again. I told them I was willing to have a deal where I was open to sharing everything I had developed with them as long as it wasn't exclusive. They weren't open to that.
ZIERLER: How does this work, if you're also suspicious that they're not so interested in electric cars?
COCCONI: That's why I wasn't wanting to be only with them, because I wasn't quite sure what their motives were, and I didn't want to be stuck with only one avenue. Some parts of GM had some interest in electric cars, but when I saw what they were doing to the EV1 program, I just wanted to make sure I had my independence.
ZIERLER: To what extent did this constitute a real change in direction in terms of your career style? Up to this point, you had always been a consultant, but now with the creation of this company, you were obviously in the inside.
COCCONI: It was a change, actually, having to try to run a company. Luckily, I had some help there. The others helped out with their part, and I stayed more on the engineering side of it. Yeah, it was a new experience and kind of exciting at first. After many years I realized I wasn't a very good manager, and I'm not really cut out to run a big company, or any company. [laughs]
ZIERLER: What was the division of labor between you and Wally and Paul?
COCCONI: We were all involved in engineering to some extent. Wally helped organize some of the legal stuff to make a corporation, which was a big help. Paul brought more of the manufacturing experience from the Hughes Aircraft, which was very useful as well. That's basically how we built the team and started going. We all worked without pay for quite a long time, a couple years.
ZIERLER: This was entirely self-funded between the three of you, at first?
COCCONI: Yes, no outside funding at all.
ZIERLER: What were the startup costs? How much into debt were you willing to go right at the beginning?
COCCONI: I wasn't going into debt. I was just using my own savings. I didn't borrow anything.
ZIERLER: What were some of the surprises in budgeting, in terms of thinking about annual costs and when you might see a return?
COCCONI: Again, we were open to trying. We got orders for drive systems relatively early on, for a few of them. We knew we had some sales ahead. Some people like Edison and other people wanted to do an electric car. The Air Quality Management District I think ordered some stuff from us. So we had some customers lined up, and we obviously hoped to get more, and we actually did. But it was a start, and we managed to survive off of that.
ZIERLER: Alan, where is the timing in terms of the small but dedicated fan base of GM's EV1 and how upset people were when GM took them back? Were they looking for a new product? Would you be able to fill this niche?
COCCONI: Not really, because our prices were high. We were more R&D-oriented. We weren't an efficient manufacturer. We were building everything by hand, one at a time, so we really didn't have products for those people. We were more aiming at people wanting to invest in the technology or evaluate our new technology, because at the time it was kind of the best available. That's the market we were going after. We realized we were not in a position to provide vehicles for consumers.
ZIERLER: Take me to your garage and really day one when you commit to AC Propulsion and building cars yourself. In terms of infrastructure, what do you have already at your disposal, and what do you have to go out and find or make connections to get these things?
COCCONI: I didn't have a dynamometer or anything, so I was kind of flying a bit blind on the first car. I did get it running and kind of used the car itself as a test bed. I just worked out of the shop in my house for that. As soon as we started AC Propulsion, we started going to all of the surplus used equipment sales and buying what equipment we could afford to do the job better. We soon built the dyno which is essential for electric vehicle development. You have to have a dynamometer.
ZIERLER: I wonder if you can explain that. Why is that dynamometer so important?
COCCONI: Because you have to be able to test the motor on the bench with all the equipment around it to measure and understand what it's doing with the electronics in order to fine-tune it and perfect the design. Testing in a moving vehicle is a nightmare. [laughs] Because you have to drive while you're doing this. You can't put the equipment where you want. Then the road never has the right hill or the right condition for the test you want to do. It's essential to have something in the lab where you can run the motor full power or any power level for extended periods and check everything out.
ZIERLER: Alan, what about the battery park? Was this going to be the same as EV1, or were you looking at different technologies?
COCCONI: At the time, there was no choice but lead acid. We were just using commercial lead acid batteries, available for the car starter industry.
ZIERLER: Lithium ion is just not available at this point.
COCCONI: No, it didn't exist at all, not even in laptops. It was not available as a product at all. We started in 1991, and it wasn't until 2000 that lithium ion became a reality.
ZIERLER: What were some of the obvious limitations to lead acid?
COCCONI: The energy density is low, and so the car is heavy and doesn't have much energy, so you have to build very efficient cars, which in a way is good training, which unfortunately many people have forgotten. For example, the Honda CRX—at the time, the speed limits were lower, so you were driving 55 miles an hour. But at those speeds, it was in the order of 100 to 110 watt-hours per mile, while if you look at most of the modern EVs like the Tesla Model 3 or even my Hyundai Kona, you're lucky to get 200 watt-hours per mile driving very carefully. We managed to make very efficient cars, and luckily at the time, the cars you could buy like the Honda CRX was smaller and lighter than what's available today, which helped.
ZIERLER: Was the business plan always to take stock frames like a Honda CRX and put your own technology into it, or did AC Propulsion always envision from the beginning building an entirely new car from the ground up?
COCCONI: That wasn't really our department. Our forte was in the drivetrain technology. We put them in the best demonstration vehicles we could find, because to build a whole car as a company of four or five people, it's very difficult. We made a big effort to do the best job possible with the cars we could buy easily, and I realized that eventually somebody would have to make a good car or hopefully they would. But that wasn't really our department initially. Eventually, the tzero project kind of changed that approach. We started off as a demo and figured out we could probably that way sell a few cars at a very high price, because it was a more attractive vehicle than a converted low-end Honda. That happened in the late 1990s. We saw Piontek in Detroit was building gasoline-powered—they called it the Sportech. We went to visit them, because we heard about the car, and realized you could make a good electric out of a modification of it, so we bought rights from him and a prototype, and modified it to make what became the tzero.
ZIERLER: How did you first hear about this company in Michigan?
COCCONI: I think through some Road & Track, or or some other auto magazine had a review of one of his cars. He probably built four or five of them. He hadn't built very many.
ZIERLER: What was attractive about this design? Why would it work well for AC Propulsion?
COCCONI: It was very lightweight. It kind of had some curb appeal. It was an interesting little sports car. And looking at the configuration, we saw there was room for batteries without ruining the look of the car at all. We could hide the batteries in the side panels quite effectively.
ZIERLER: What was the original business arrangement? Did you want to buy the design, or did you want to partner with him?
COCCONI: No, we bought the design and a prototype car. He built it. So we never partnered with him. He really didn't have any manufacturing capability…he was building them, again, in his garage by hand, so he didn't have anything to offer in terms of manufacturing.
ZIERLER: What exactly was the arrangement? You bought the design, and then you can build it yourself, or he would continue building it?
COCCONI: Yeah, we bought the design. I think we had to pay him royalties of $1,000 per vehicle we sold, which didn't amount to much because we only sold two of them. [laughs]
ZIERLER: Basically, between the founding in 1992 of AC Propulsion and then later on in the decade, what is AC Propulsion doing? Is it all CRXs?
COCCONI: We converted vehicles for other manufacturers. We did quite a few Volkswagens, because we got a decent contract from Volkswagen to do some demo cars for them. We did an early Beetle. We did a Volkswagen Rabbit and a Jetta. We even did a hybrid Jetta for them. So we did several cars for Volkswagen. We actually sold a Honda CRX to Volvo, another one to Honda, I think. So we built several cars for customers, and we sold quite a few drivetrains. We sold probably I think 50 or 60 drivetrains to various university teams or automakers who wanted to test them.
ZIERLER: Were big companies like Volkswagen, were they excited by this technology? Did anyone ever approach you about mass production of electric vehicles?
COCCONI: We were hoping for that. They weren't approaching us. We were approaching them, trying to get some initial interest. We did get the initial stuff, but with Volkswagen it became clear they really wanted to work with their usual suppliers like Siemens, etc. They saw us as an interesting technology demo, but they weren't taking us very seriously in terms of becoming part of their future program. At the time when we talked to Volkswagen, I got a very good quote saying that their future was with clean diesel. [laughs] They actually told that to us very clearly from high levels of Volkswagen. That's what they were really betting the future of Volkswagen on. Electric was kind of not on the books.
ZIERLER: What were some of the regulatory issues you came up against? If a consumer came to you and said, "I want one of these," what do you need to do in terms of making the car street-legal?
COCCONI: In the U.S. the rules are pretty lax about that for low-quantity cars. Even for the tzero, it wasn't that hard to register them as an experimental kit car type thing. If you're only building a few of them, we certainly made it very clear to the customers we weren't meeting any of the official safety regulations and it was sold as an experimental non-safety-certified car. That's what we did for these customers. On the conversions, you can just keep the original registration, and nobody was really paying attention to what happened to the drive systems. That's how we did many of the conversions.
ZIERLER: When did you get the tzero finally and fully operational? What year was that?
COCCONI: I think something around 1997. I'm not exactly sure of the date. It was fully operational with lead acid batteries.
ZIERLER: How much better was it than retrofitting a Volkswagen Beetle or a Honda CRX?
COCCONI: It was much lighter, so the acceleration times were much faster. We got zero to 60 in I think around four seconds or so, between four and five seconds. The range was actually not quite as good as the CRX. It was a less efficient car than the CRX even though it was smaller, because the aerodynamics wasn't so great in the tzero.
ZIERLER: Why is that? It certainly looks like it's slippery in a wind tunnel.
COCCONI: No, it's got the chopped rear window that's vertical and not a fastback, so that's kind of bad. It's very small, which redeems it, so it's not that bad because it's so tiny, but in terms of its shape, it's not great for aerodynamics.
ZIERLER: Where would you take it to really push it to its limits? What tracks or even canyon roads were useful for testing the tzero?
COCCONI: We did some testing. In fact, we had some handling problems initially with some unsafe handling at high speed which we sorted out. Road & Track actually gave us a lot of input on that. They were interested in the car. When they had access to Pomona Fairgrounds for their vehicle testing and the skid pad area there, they invited us to come along and let us drive other cars to compare them and to try to understand what problems we had to fix. So Road & Track helped us a lot.
ZIERLER: Did the car have regenerative braking also?
COCCONI: Yeah, all our cars did. That's from day one.
ZIERLER: What kind of range in real-world conditions did the early tzero get?
COCCONI: About 100 miles in real-world conditions with lead acid batteries.
ZIERLER: In terms of charging, is this just a standard 110-volt connection?
COCCONI: No. We pioneered AC Propulsion with what was called integrated charging, which meant that when the car was not moving and you plugged it in, the electronics that drove the car became the charger. It used the motor and the same electronics to charge a car from 240 or 110 volts. On a 240-volt 80-amp outlet with lead acid, we could do a full charge in one hour.
ZIERLER: This was the real divergence from GM and where they wanted to go?
COCCONI: That's right.
ZIERLER: Why is it better?
COCCONI: There was no charge infrastructure at all at the time, in the country. With that approach, you could go to any RV park and plug in and get a fast charge. We did that on long cross-country trips. It gave you the possibility of charging in many places which had no official infrastructure. Even at home, all it took was a dryer outlet you installed in your garage, and you could charge—with the 50-amp service, you could charge in an hour and a half. So it was a very practical approach, and the cost was low because there were really no additional components, or very few, to make the charger, because it reused all the drive components. Which obviously when you're charging, you're not driving, so you can use them for something else. That was kind of our innovation and some of our patents were on that, on how to reconfigure the drive system to make a charger.
ZIERLER: When is AC Propulsion starting to make money? When do you go from living off your savings in terms of having a sustainable business?
COCCONI: After we got a few sales, and like these contracts from Volvo and Volkswagen, etc., we could hire more people. At some point, we were just over 20 people, I think. Something around 20 people. We had quite a bit of business coming in and we were surviving. Once in a while I kept on pouring more money in, but not all the time.
ZIERLER: Were there international customers as well? Were there clients in Asia and Europe that were interested in this?
COCCONI: Asia, not so much. We were dealing with Volkswagen in Europe, so that was European. Eventually, after 2000, after I started distancing myself from AC Propulsion is when they got the BMW contract for the Minis, where BMW had to meet a California pollution regulation and have x number of EVs on the road. I think they built close to 1,000 of them using our drive system, so that was a major contract for AC Propulsion.
ZIERLER: Did you have interaction with John Fagan at the University of Oklahoma?
COCCONI: Yes, we did. He bought some drive systems and built cars using our drive systems.
ZIERLER: What was the distinction? What was he doing that was different from you?
COCCONI: He was building cars. We were supplying him components. That's what we wanted to do. He was at the car-building side, not the electronics side. We were happy to send him drive systems and electronics and motors and battery management systems. He dealt with the rest.
ZIERLER: By the end of the 1990s, early 2000s, are lithium-ion batteries starting to come online?
COCCONI: That's when I noticed the batteries being used in laptops started to have enough power and energy. You need both for an electric car. You can't just have energy. You also have enough power to accelerate well. They started to have performance numbers that were usable. As I said, I first noticed those batteries and started using them in my airplanes. That was the first pack of over 100 cells that convinced me that this was viable for electric cars. At the time, we studied and saw we could put them in the tzero, but we were kind of low on money at the time. It was probably close to a $100,000 project to put the first pack in the tzero. That's when we were talking to Martin Eberhard about this. We knew we could put these batteries in the tzero. He invested in AC Propulsion enough money to let us do that. He supplied I think just about—I can't remember exactly but I think basically all the money we needed to put the lithium ion pack in the tzero.
ZIERLER: The airplanes you were building, was this your own thing, or this was part of AC Propulsion?
COCCONI: No, it was my own thing on the side.
ZIERLER: Why did it make more sense to experiment with lithium-ion in airplanes before cars?
COCCONI: Because it was only 100 cells, not 6,800. [laughs] It was easier to do, and I was interested in the airplane stuff at the time. It was a good way to get some experience with them. A hundred cells, you can assemble in a few days, while 6,800 takes a bit more effort. [laughs]
ZIERLER: How did you first meet Martin Eberhard? Where was he around?
COCCONI: I think he had heard about us and then wanted to come and discuss electric vehicle technology, and we showed him what we were doing. I'm not sure exactly how he heard about us, but we were in the press on and off, quite a bit, so it's not too surprising that somebody with interest in electric vehicles knew who we were.
ZIERLER: Was he looking to be an investor of AC Propulsion, or did he want to buy the technology for his own company?
COCCONI: At first, he wanted to be an investor in AC Propulsion. When he saw how well the tzero worked, he wanted to start his own company and offered to provide financing and basically dilute me out of ownership of AC Propulsion, which I wasn't willing to do. I said, "No, start your own company. I'll stay with AC Propulsion." I didn't want to be a minority stockholder in this new company. At the time, that was not attractive to me. He ended up buying the technology rights, and we helped him with the first prototype of the Lotus Elise, which became his roadster. His first Roadsters he sold were all based on the Lotus Elise frame. We helped him build the first prototype and some of the engineering work on that. Soon he had a facility and took it over and went on from there.
ZIERLER: What were some of the key differences between the Lotus and the tzero?
COCCONI: The Lotus was more of a real car. The tzero, you couldn't even drive it in a heavy rainstorm without things getting wet that shouldn't be wet. It was really just a fun car for a nice day and maybe a little bit of drizzle, but it couldn't deal with real weather conditions and wasn't a real car. It was a demo vehicle. I used it as a real car. Actually we did a camping trip to Yosemite and everything in that car, using the hybrid trailer. But you had to be dedicated to use that car every day, while the Lotus Elise was built on a real platform that had proper doors that sealed and heating and windshield wipers that actually worked and all that stuff. It was a real car, and it weighed a bit more than tzero, so the efficiency was a bit lower. But it was the best thing they could do for startup like Tesla at the time, and not to have to build their own car. Again, building your own car is an enormous task, so was much easier for them to partner with Lotus and buy the chassis from them.
ZIERLER: How much consideration did you have to make the tzero less of a novelty? To waterproof it, so that it really could be for everyday use?
COCCONI: Again, we didn't have the necessary financing, and raising money isn't one of my strong points. We knew that it needed a lot of development to become a real product, but we weren't really in a position to do it. Martin Eberhard had more access to capital than we did, to take it on. We said, "Fine, go with it."
ZIERLER: When did Tom Gage join AC Propulsion?
COCCONI: In the mid 1990s. I don't remember the exact date, but he came in having had experience in Chrysler as a mechanical engineer and product manager, and had done various work in auto companies. He was a business major as well as an engineering degree, so he brought a lot of expertise we didn't have. I think he was working at SAIC or some company like that doing a study on electric cars and learned about us, and came to talk to us, and then asked if he could join us.
ZIERLER: I don't know if I'm pronouncing it right, but what was the Challenge Bibendum?
COCCONI: Challenge Bibendum was one of these electric races which we helped a customer, which was Madam Courrèges in Paris. She does fashion shows, she's a fashion designer, but she got interested in electric vehicles and wanted to enter these races with an art-inspired car, and she built a couple of them, and we helped her out with drive systems and technical support. We went to a couple of those races with her to support her efforts.
ZIERLER: Alan, you said at some point you started to distance yourself from AC Propulsion. What happened?
COCCONI: I got serious prostate cancer and was in bad health for a few years. I kind of realized I wanted to do something different with my life. I had done enough with electric cars and was getting a bit frustrated with all the politics. That's when I started doing the airplane work more seriously. I sort of distanced myself from AC Propulsion and eventually sold my interest in AC Propulsion to the Chinese investment group that are the ones who now are continuing with AC Propulsion. I stopped working there.
ZIERLER: When was that, roughly? When did you sell your interest in AC Propulsion?
COCCONI: Let me think. The final sale was probably 2007 or so, but I started backing off from AC Propulsion before that in terms of my involvement.
ZIERLER: By 2007, obviously you were around for when Tesla was up and running.
COCCONI: Yeah, they were just beginning to deliver a few roadsters. Yeah.
ZIERLER: What did you think of Tesla? Were you paying close attention to what they were doing?
COCCONI: Yeah, we were. Obviously we were interested, and we were happy to see them make some product. They were losing a lot of money at first, and luckily Musk came in who had more money to lose and knew how to get more money to lose. [laughs] So he came in and managed to increase the capital of Tesla by orders of magnitude, which let them become what they are now. Martin Eberhard kind of ran out of steam in terms of available capital. He sort of ran into the same problems that AC Propulsion had, but on a larger scale.
ZIERLER: Was your sense that Elon Musk was more excited by the Lotus or the tzero?
COCCONI: They were very similar. The Lotus was more of a real car. The tzero had been the demo that led to the Lotus, and obviously he had to evolve more in the direction of real cars. It was a progression, and the tzero kind of was the one that showed what was possible with electric cars. The Lotus was a logical progression. He picked it up from there. There's no going back to the tzero. It wouldn't have made any sense at all.
ZIERLER: As you said in our first talk, you really disagree with the direction that Elon Musk took with Tesla, given that they have such large cars and there's an emphasis on performance over efficiency. Did you see that baked into Tesla's plan from the beginning?
COCCONI: At the beginning, I felt that was a logical plan to build something like the Roadster, because again, the price is necessarily very high, because the production volume was low, and that's the only sort of car you can sell for a high price. Initially I thought the Roadster was a very sensible step. When it went beyond that, after Musk started designing these other more normal sedans, that's when he emphasized the very high-end luxury end, probably for some of the same reasons. But on the other hand, he had so much investment capital he could have built anything he wanted, and eventually made it work. He was less bound by the necessity of making a profit in the first few cars.
ZIERLER: What was your sense of Martin Eberhard's interest in taking over AC Propulsion? Was that ever considered?
COCCONI: Yes, it was, and I turned that down.
ZIERLER: Obviously Wally and Paul and Tom weren't—you were all on the same page with that?
COCCONI: Yeah, we were pretty much in agreement with that, at the time.
ZIERLER: Why was that not an attractive offer?
COCCONI: Because I guess we had been used to being in charge of our own destiny, and the idea of losing all authority and just becoming employees in a large organization wasn't really what we wanted.
ZIERLER: Although the difference between Martin Eberhard and GM is quite distinct, but as far as you were concerned, if you were working for somebody else, that's the only thing that mattered?
COCCONI: Yeah, I guess it wasn't attractive to me at the time. Also, at the time, I was trying to distance myself from AC Propulsion as well, and to take on this new role of having to support all of Martin's efforts, it's not the role I wanted.
ZIERLER: Were you so sick that you were out of commission? You weren't doing any engineering work for a period of time?
COCCONI: No, I was doing engineering. Eventually I had surgery and got over it, but that kind of made me look at my life and realize I want to do something different from electric cars. I had done enough. I contributed what I could, and it was time for somebody else to take the ball and go with it. Airplane UAV work interested me. I was committed to doing that as well as I could. It ended up being a successful project, but it took an awful lot of my time.
ZIERLER: Alan, when you thought about closing that chapter in your life, I'm sure it was an opportunity to take stock on what you had accomplished with electric cars. What were you most proud of, with all of your contributions to making electric cars?
COCCONI: Just happy to move the industry forward. I feel that it's an important technology for everybody—for all of society—and it was good to see Tesla doing something with it. I was happy to see that. At first, Tesla was kind of touch-and-go as well. Everybody was looking at what Tesla was doing and wondering if they could survive, and we were wondering as well.
ZIERLER: By the early 2000s, this is certainly the time when people start connecting auto emissions, carbon emissions from automobiles, with climate change. Do you think in terms of the politics, in terms of the economic interest, that was a significant boost for the electric car industry overall?
COCCONI: I'm sure it helped. All those things—maybe even before that, though, the air pollution thing was a relatively big reason to have electric cars. There has always been environmental and scientific reasons for encouraging electric cars, and they have intensified lately. But it's not like it was a sudden change that all of a sudden things became different. It was kind of a gradual increase in the pressure to push this technology forward.
ZIERLER: Alan, when you had recuperated, and you wanted to get back to airplanes, tell me about the airplanes. What did they look like? What models did you have in mind?
COCCONI: Initially, I was flying some commercially available five-meter-wingspan large model gliders to develop all the components, because I knew building a solar wing and a dedicated airframe was a major undertaking and was easy to damage if anything went wrong. I spent two or three years just flying large gliders with big batteries, lithium battery packs, to understand how to do all the autopilot systems, the telemetry the propulsion system. I did some night flights with those, flying for up to 12 hours with lithium batteries to make sure that I had the efficiencies and propulsion systems worked out. After all that was done, by 2004, I had a solar airplane built, which I custom designed and optimized best I could for the mission. I built a five-meter wingspan, roughly 30-pound large solar-powered glider, basically, and flew that for over a year before setting the record, because I had a lot of debugging and fine-tuning to do.
ZIERLER: Were you again right back to where you started? This was a solo operation?
COCCONI: That was completely solo. I never had the intention of getting any employees on that one. That was entirely solo.
ZIERLER: From a financial point of view, did selling your interest in AC Propulsion provide all the startup funds you needed for this?
COCCONI: I didn't need that many funds for solar airplanes, since my labor was free and the materials weren't that much. That wasn't a big consideration.
ZIERLER: In terms of your motivations, looking at the distinction between the importance of building electric cars versus electric airplanes, were they basically the same in terms of efficiency and resources, or were there a different set of circumstances motivating the airplane work?
COCCONI: The airplane work I knew as a societal thing for emissions, etc. it was much less important than electric cars. It was kind of to see if you could do these permanent airplane communication platform-type products, which is always the goal of these solar-powered airplanes, which actually to date nobody has really done in any commercial way yet. It's not much beyond the stage where I left it. A bit better, but not much. Still difficult and not quite practical. But I guess I was just interested in the challenge of doing it, to see if I could combine my understanding of aircraft design and aeronautics and all the propulsion technology, which I learned from doing electric cars and other projects, into the complete airplane product. For me, that was a challenge, and I've always liked the airplanes and the flying stuff. It has always been a hobby of mine. I can't really justify it in terms of any overall environmental goal or anything like that. It was just a personal challenge, and I saw this chance for me to be the first person to do it.
ZIERLER: The first—exactly what? How do you define the first? What was the goal you set for yourself?
COCCONI: The goal was to show multi-day sustained flight on solar power. Nobody had ever done that. When I managed to do 48 hours, you can show that you have the capability of going on for much longer. Since I had no paid support team, it was all volunteers, two days was enough. That was enough to show it. One day isn't enough to show continuous. If you can do two days, you can basically extrapolate much longer very easily.
ZIERLER: Was there anything from the Sunraycer project that was useful to you for the airplane work?
COCCONI: Yeah, the Sunraycer and also my very first photovoltaic converter, which I did for the residential stuff, for the rooftop solar. A lot of those technologies, I had been thinking about them and learning techniques during those projects. So yeah, I applied everything I knew to the solar-powered airplane as well.
ZIERLER: What airport did you use for this work?
COCCONI: I did a lot of flying up at El Mirage dry lake, and actually the record was done at Desert Center, which at the time was an abandoned U.S. Air Force strip from World War II. In the last 15 years, it was converted to a motorcycle racetrack, so it's no longer available. But back then, it was basically an abandoned air strip out in the middle of the desert between Los Angeles and Blythe. I used that strip, and it was a good location, because the winds were low. It was at a suitable low altitude. You get the higher air density. There was nobody around to bother, and you could camp out on this air strip for days and just use it. That's what I did. I didn't ask for permission; I just did it.
ZIERLER: Did the airplane use lithium-ion batteries?
COCCONI: Of course, yes. That's the only thing that made it possible.
ZIERLER: Lead acid would have simply been too heavy?
COCCONI: No, it would have been off by a factor of six. [laughs] With the best lithium-ion batteries at the time, it was barely possible. Now, lithium batteries are almost twice as good as the ones I had then, but those were the first ones, and it was all I could get at the time. When I did that project, I knew some people at NASA, at Edwards Air Force Base, from my previous work. I talked to them because I realized being able to fly for 48 hours—it was a marginally legal thing to fly all night in uncontrolled air space. I asked them if there was any way I could use the air place at Edwards Air Force Base for this record flight. That ended up being a big boondoggle. They hired a person full-time for four or five months to try and get all of the permissions through the system at Edwards Air Force Base. I had multiple meetings and safety discussions and all these studies, and they basically couldn't do it. They couldn't get through their own paperwork. So when the weather was right, and I was ready, I just went out to Desert Center and did it, and called them after the fact and said, "Sorry, you can cancel your program. It has been done."
ZIERLER: Who certified the record? Was Guinness involved?
COCCONI: No, it was not Guinness. Some press came out there. I think one of the news stations came out. I had quite a few people who were well-known in the model airplane circles who were there and basically corroborated it. I didn't do it in any official way.
ZIERLER: Who took notice of this? What was the impact of achieving the record?
COCCONI: I got a nice article in Aviation Week. [laughs] That was probably the biggest impact.
ZIERLER: What year was this?
ZIERLER: Did you see this more as a novelty, or looking out into the future, is there some market for solar-powered electric airplane flight?
COCCONI: Yeah, there is some market. Unfortunately, the usual thing—the military is part of the first one. But the hope, eventually, is to kind of do what actually Elon Musk is doing now with the many small satellites, filling the sky with thousands of satellites for doing this worldwide internet. The idea was if you can do these airplanes that can stay up all year long, you can do internet in remote areas more cheaply than wiring it. That's always the idea; if you can do a communications platform that stays up and is cheaper than launching satellites, then you might have a real business. It's not easy to get to that point. In the interim, the military loves this stuff for spying on battlefields for extended periods. That's the other application, which I was not interested in.
ZIERLER: Is this a company that you built, or this is just your own personal project?
COCCONI: It's my own personal project. I still have the airplane. I last flew it a few years ago. It's just mine. It's not much more than a hobby.
ZIERLER: Is there proprietary technology that you can license out if you want to?
COCCONI: I don't know. Probably not proprietary, but a lot of know-how about how to do this well. I actually sold some of the components to Qinetiq, which is a British aerospace firm, at the time they were working on a commercial project which of course eventually became military, like they tend to. They bought some motor drives and stuff from me, of the type I use in my airplane. They went on to do a one-week flight a few years later.
ZIERLER: Just to bring our conversation right up to the present, from 2005 to now, what have you been up to? What have been some of the other things you've been interested in?
COCCONI: I worked some with Solar Impulse to do the solar peak power trackers for their airplane that flew around the world. Have you heard about that project?
COCCONI: I designed their prototype peak power tracker system for them, and I tried to give them some input on the overall project, some of which they listened to, some they didn't. In fact, I had warned them the battery needed a cooling system, and they told me that the manufacturer assured them that it didn't. In the end, the batteries overheated and caused them a one-year delay in their round-trip world flight, so I wish they had listened to me! [laughs] They got stuck in Hawaii for a year, because it destroyed the battery packs on the Pacific leg. But that was an interesting project to work with. Then as I mentioned in the writeup I gave you, I got involved more as a hobby in this dynamic soaring stuff, which ended up taking a fair amount of my time.
ZIERLER: Tell me about that. What does that mean?
COCCONI: That consists of flying model gliders, basically, just flying them visually, no closed-circuit TV or anything. But you fly on a mountain ridge where there's a high wind above the ridge and sheltered air behind it. With a particular flight pattern, you can go up to ten times the wind speed, flying an oval pattern. There are a few people in the world doing this. It started, again, around 2000, I think, when this phenomenon was first exploited by Joe Wurts, who was an aerodynamicist at Lockheed, also a model airplane flyer. He started it, and I saw some of the early flyers doing this, and it looked interesting. It's a very unusual aerodynamics phenomenon, of how you can use this weird wind situation to get these tremendous speeds and a tremendous amount of power. I got hooked on that and spent a lot of time developing electronics and servo systems. I didn't actually do the airplane design. I've done parts of airplanes for some design changes, but I was more interested in the electronics and other aspects of it, and telemetry systems for it.
ZIERLER: The Swiss Solar Impulse project, is that still around?
COCCONI: It's still around, and it has become military, like they all do. [laughs] I heard they got a contract from the U.S. Navy to spy on China.
ZIERLER: You're no longer interested as a result?
COCCONI: No. [laughs]
ZIERLER: Then the servo work you did, developing brushless servos?
COCCONI: Brushless servos, yeah. As I got back into the airplane work, I realized that existing servos were not very good, especially for these long-duration flights. They wore out. I wanted to apply some of the motor technology I knew to that industry, and I made some of the first brushless servos in the industry.
ZIERLER: What exactly does brushless mean? What is a brushless servo?
COCCONI: Most small little DC motors have carbon brushes sliding on a commutator, while the more modern motors like are used in more industrial applications or electric cars all have electronics doing the switching, so there's no sliding contact. The motor basically has nothing to wear out. It's just a rotating part with some bearings, but there's no graphite brushes sliding on copper that eventually wear out. You can make motors higher power, and they generate less heat, and life is way, way better with the brushless approach. But doing it in the tiny size needed for model airplane servos is somewhat tricky. I saw a need for that and started developing these products.
ZIERLER: Are they still around today, these brushless servos?
COCCONI: By now, quite a few people are making brushless servos independent of my effort. They probably saw my example and copied various bits. Hitec is still licensing my technology and making thousands of these a year. Hitec is in Korea, one of the major servo manufacturers in the world, and they are making a line of servos based on my design.
ZIERLER: Where do we see these? What consumer products do we see these in?
COCCONI: Not consumer products. These are sold to the model airplane industry, to the hobbyists.
ZIERLER: I see, I see.
COCCONI: They've been well-received and work very well. It's an ongoing manufacturing concern on their side. Once in a while, I support them with some software development, etc. But that has been a successful product. Another product I got involved in—I always try to think of what industries are lacking in terms of missing a product that I know how to do. I ended up developing a fiber optic isolated oscilloscope probe for power electronics work. It's something I kind of always wanted when I was doing the electric vehicle drives, and nobody made it. When I had some time and was thinking about what a neat product would be to develop, I started work on that and ended up licensing it to LeCroy Oscilloscopes. They are now manufacturing those, and they are used exactly as I thought they would be used.
ZIERLER: I wonder if you can explain, what is a fiber optic isolated oscilloscope probe?
COCCONI: When you're working with high-power electronics, often you want to look at relatively small signals, five- to 20-volt signals or even smaller, that are riding on hundreds of volts of power circuits. You cannot attach the oscilloscope directly to the point of interest, because the circuit you're interested in is electrically floating with all kinds of high frequency switching going on. It's very difficult to look at what these circuits are doing when they're actually operational in a motor drive, because your oscilloscope is grounded, and the part you're interested in is this weird high-voltage circuit that it's very difficult to get information out of. If you can make something that has fiber optic communication to the oscilloscope, you can tie it to this dangerous high-voltage circuit in a safe way that doesn't upset the operation of the circuit, which makes it very versatile and allows you to understand what's going on in your circuit in the actual application, which is very valuable when you are developing a new product.
ZIERLER: Where do we see this in applications?
COCCONI: The people designing photovoltaic converters, electric cars, all kinds of industrial motor drives, any high-power motor drive or AC inverter application is where you'd use it.
ZIERLER: This is what you sold to Teledyne LeCroy?
ZIERLER: Where have they put these products? Have they licensed them out, or these are all exclusive to Teledyne?
COCCONI: They're exclusive to Teledyne. They sell them along with their oscilloscopes. That's one of the accessories. Various customers who are doing that kind of work purchase these to go with—Teledyne LeCroy specializes in very high-end oscilloscopes, with very specialized software and extreme performance capabilities, so this went along well with their product portfolio.
ZIERLER: Your interest in dynamic soaring, is the only power source the wind, or is there a motor on board?
COCCONI: The only power source is the wind. You hand-launch these airplanes into the wind, and then you fly them in a pattern that slowly whips up the speed. In probably ten laps or so, you can be going 500 miles an hour.
ZIERLER: Are there flaps? How do you control the plane?
COCCONI: The usual control surfaces, like any airplane. It has the flaps for landing, and elevator and ailerons for steering, you control it like a normal airplane. But the flying, you're doing two- to three-second laps at 400 to 500 miles an hour, at about 100 feet above the ground, so the piloting is quite intense. [laughs]
ZIERLER: How big are they?
COCCONI: The ones I fly are two-meter wingspan. The larger ones go to like three-and-a-half meter.
ZIERLER: Obviously they're light enough where you can just launch them manually?
COCCONI: Yeah, the largest models can weigh up to 100 pounds. The small ones I fly can weigh about eight or ten pounds.
ZIERLER: How do you launch a 100-pounder?
COCCONI: When the wind is blowing 50 miles an hour, basically all you have to do is hold it up and take a few steps forward and let go.
ZIERLER: Is this also just for hobby, or are we seeing this in applications for industry?
COCCONI: No, what I always say about this is the beauty of it is it's completely useless.
ZIERLER: [laughs] No concerns about the military coopting it, you mean?
COCCONI: That's right. That's why I like it. [laughs]
ZIERLER: Now that we've worked our way right up to the present, for the last part of our talk, I want to ask a few broadly retrospective questions, and then we'll end looking to the future. In all of your work, in electrifying these things, what has been the most fun for you? Of all the projects that you've worked on, what has been pure fun?
COCCONI: Probably the solar airplane was one of the most interesting projects for me, because there was no politics, no financial pressure. It was just the pure technology of achieving the result. That was an amazing project to me. I thoroughly enjoyed that one.
ZIERLER: It's almost a shame that you need to make money in order to do these things. It takes away from the purity.
COCCONI: Yeah. For me, I don't do very well dealing with all the various policy and political implications, and necessities of the other projects. The solar airplane was a nice break from that. It also combined a lot of my interests, from the aerodynamics to the power electronics to the flying. It was a great combination.
ZIERLER: In total, what do you see for your contributions in terms of addressing all of these major problems that we're faced with, that you're so concerned about, with air quality, and resource extraction, and carbon emissions?
COCCONI: I'm glad to have contributed. I think through Tesla and the tzero and others, we've managed to show the whole world this is real and needs to be done. I think that's very important, and I'm glad to have played a role in that. The EV1 did initially. That fizzled out, but I think it really took Tesla to show the world that it really can be a business, and that people do want these products.
ZIERLER: Where we are today relative to your earliest work in electric cars, are you impressed? Are you impressed with the level of adoption, or should we be farther along, according to what your earliest hopes were?
COCCONI: I wish we had been further along. I think if it hadn't been for Tesla, we wouldn't be anywhere near where we are now. Tesla has forced the other automakers to wake up. They're still catching up a bit, and some are catching up better than others, but at least now they're all sort of on board at some level, understanding this technology at least deserves some serious attention.
ZIERLER: Finally, Alan, looking to the future, let's start first with your concerns. Of all of the things that you're concerned about that have motivated you throughout your career, what are you most concerned about?
COCCONI: What do you mean by concerned about?
ZIERLER: In terms of the problems for which electric cars and other technologies that you've developed are responsive to.
COCCONI: I guess the environmental aspects have always been important. Electric cars have always been presented and in my mind an important part of the solution to the various environmental problems we have. Everything from basically using less resources of all kinds is an important aspect of them. That's why I'm always on the efficiency side, because if you build very bad electric cars, you kind of undermine some of that progress.
ZIERLER: Finally, ending on a note of optimism, in terms of all of the things that have been accomplished so far, what are you most optimistic about, in terms of the technology, in terms of the consumer demand, and in terms of actually resolving some of these very difficult environmental and resource problems?
COCCONI: The electronics technology has come a long way, so now doing the electronics of these cars is much easier than it used to be. The components are better and cheaper and more reliable, and the batteries are also getting much better. It's clear that the technology is making this a much easier effort to support. That's very encouraging. The fact that all of the auto makers are now putting serious R&D commitments in this area means that there will be progress. Some of it may not be entirely rational initially, but eventually, auto makers evolve their products in a direction that ends up being quite rational given enough time.
ZIERLER: That's always the factor. Even from a tiny endeavor like what you started, finally we'll see widespread adoption on a global scale.
COCCONI: Everybody is talking about that now, and I hope it doesn't fizzle out completely. I don't think it will. I think we're at the point now where it is going ahead, and how fast it goes ahead is still open to debate, but I think that the fact that it is moving forward that way, and all the automakers that you know are making serious commitments in this direction.
ZIERLER: On that note, I'd like to thank you for spending this time with me and for sharing your recollections and insight. It's a tremendously exciting and important career that you've led, and I'm so happy that we were able to capture it for this oral history. Thank you so much.
Alan Cocconi added the following passage, subsequent to the interview:
A topic that I had mentioned in the work history I sent you before the interview did not make it into the discussion:
This is the fact that Tesla was the only manufacturer that appreciated and understood the advantages of using thousands of small cylindrical lithium cells as demonstrated in the tzero instead of the much larger ones favored by all the others at the time. This allowed them to avoid many of the problems that GM, Hyundai, Nissan and others have had with their approach to battery construction, and this has contributed to Tesla's dominance in the early EV market.
Another related issue is that AC Propulsion also showed that the use of many (we used 12 for each switch) smaller power transistors in parallel had advantages in terms of efficiency and cost. Again, Tesla was the only early adopter of this approach, which was a significant advantage with the power semiconductor devices available at the time.