Builder of a 1975 Porsche 914 All-Electric DIY Conversion Fills Us In on The Process

I love stumbling across alternative vehicle DIY solutions on the Internet. And, after viewing the above electric Porsche 914 video, I was curious about the person in the clip and decided to contact him to see if he had any nuggets of info he could pass on to others interested in converting a conventional car to electric. As it turns out his name is Ross Cunniff. He’s a software company director by day, and electic car enthusiast by night with two degrees — one in math and another in computer science. He was happy to let others in on his project and agreed to answer a few questions.

Q: What got you interested in electric vehicles?

A: I’ve been concerned for quite some time about the environmental impacts of single-passenger driving habits. Between peak oil, global warming, air pollution (both particulate and ozone), and water pollution (from gas stations and refining) I am convinced that we need a better way to get around town. My own personal commute is less than 15 miles round-trip, and I knew that this is similar to many others – the typical daily driving distance is less than 30 miles. So, all of this combined to push me toward wanting an electric vehicle, and to advocate for their widespread use.

Q: Do you have a technical education, or work in a technical profession?

A: Yes to both. I’ve worked for 25 years in the computer industry, mostly at the lowest levels of software (drivers, operating systems, etc.). This has given me familiarity with many engineering concepts, such as designing proper experiments, collecting and analyzing data, and how to find knowledge and apply it to a problem.

Q: What led you to deciding to convert your Porsche?

A: My interest in electric vehicles initially made me want to buy one. But there were not really any good options for prebuilt vehicles when I was searching in 2004. After doing some research, I found out that the Porsche 914 was a nearly ideal conversion “donor”. It has front and rear compartments, is light and aerodynamic, has many original and after-market parts available, and has a relatively simple electrical system.

So, in 2005, I found a suitable 914 about 100 miles away that I purchased specifically to become an electric vehicle.

Q: How did you find the electric motor and battteries you chose to use for it?

A: My research into EV conversions had led me to one company who provided kits for converting Porsche 914s. I ordered their kit in the fall of 2005. I did not fully appreciate the magnitude of what I was getting into – the “kit” turned out to be fairly incomplete, with inadequate instructions. I believe that company has since greatly improved their kit, based on feedback from me and others who were converting at the time.

As I was building the kit, I found several communities of converters who were able to help me find sources for various components. These communities are still around, and are very helpful (two big ones are at diyelectriccar.com and evdl.org). You can get all sorts of recommendations on component providers and design considerations from fellow EV conversion enthusiasts.

Q: What was the cost of the electric technology?

A: I went “high-end” for the time – AC motor and controller, and 144V battery pack size. This translated to about $14,000 in cost for the elctric components. People could do a simpler conversion for probably around $8,000 today.

Q: How long did it take you to plan the gas to electric conversion process?

A: Since I purchased a kit, the “planning” time was less than you might otherwise expect. The actual conversion process took about 3 months of part-time work.

I have since done a conversion from scratch of a Jeep Cherokee. That took about 1 year from start to finish, including planning time and building / debugging time.

Q: Were you able to complete the conversion at home?

A: Yes, entirely in my garage at home.

Q: How many hours did you spend on the conversion, and did you undertake it by yourself?

A: Not counting all of the effort spent on restoration of the 914 to robust driving condition, I probably spent about 400 hours on the conversion. I probably spent closer to 1000 hours on the Jeep Cherokee conversion, since there was no “kit” available.

Q: Were there books, or websites you used to refer to when you had a question or problem?

A: Yes, many. In addition to the above websites, there are several blogs on conversions. I also read a book by Mike Brown (from Electro Automotive, the provider of my kit) called “Convert It!”.

I’ve documented most of those links at my Volt914 blog.

Q: How long do you expect the batteries to last?

A: I replaced the original batteries after 2 years. Not because they were worn out, but because I had decided that flooded lead-acid batteries were not a good technology. I have replaced them with sealed lead-acid batteries, at a higher overall voltage. I expect the new batteries to last 3-5 years with the kind of discharge / charge cycle that I maintain (I very rarely discharge below 50%).

Q: Your video shows you driving in cold weather. How much does temperature affect the battery performance?

A: Cold weather can definitely impact range. At freezing, range is roughly half what it is at “room temperature.” And range goes down even more rapidly below freezing. With my battery upgrade, I am also adding battery warmers which will both extend my cold-weather range as well as improve the lifetime of the batteries.

Q: Are you going to convert any other vehicles?

A: As I said, I have already converted a Jeep Cherokee. I am planning an electric scooter project. And I am also likely to do an electric-assist 3-wheel velomobile (human-powered tricycle). I seem to have caught “the bug.”

Q: Would you buy a new electric vehicle from a dealer, or prefer to convert a used vehicle?

A: I am considering buying a Nissan LEAF or Chevy Volt when they become available. Mostly to replace the family car (the 914 only seats two people).

Q: What is your dream car?

A: Tesla Roadster. If I ever find $150,000 lying around with nothing better to do with it…

Jake Richardson

Hello, I have been writing online for some time, and enjoy the outdoors. If you like, you can follow me on Google Plus.