Building An Electric Vehicle
An electric vehicle primer.

Mark Brueggemann K5LXP
October, 2002

Many folks have emailed me about how I built my electric truck, and want to know what they need to do to build their own, or where they can get plans. Rather than retype the same note over and over again for general information requests, I typed up this info page which should answer most questions. I really enjoy detailed debates on technical issues, so if you have any questions about the how's or why's of EV's, please send your inquiries my way.

Why Drive an EV?

First off, I built my EV not because I'm a tree hugger but because the idea of an electric car has always intrigued me. I bought my gasoline Chevy S-10 virtually new in 1986 and as it turns out, S-10's are one of the more widely converted vehicles to electric. Mark B's S-10 The initial "sticker shock" of some of the EV component costs (motor, controller, batteries, etc.) made me think twice at the outset, but as years and miles accumulated on the truck, the idea nagged more and more. The turning point was discovering there was an Electric Auto Association chapter right here in Albuquerque, and at my first meeting got to meet folks who not only had the same interest, but had real electric cars to drive. After much investigation and self-education on all the pertinent facets of building and driving an electric car, the plans were set in place to convert my S-10. I used only current mainstream parts and processes, I wanted to leave little to chance that this project would fail. It turns out (in hindsight) that it was wildly successful, after several years and tens of thousands of miles of use there have been virtually no unexpected problems. For day-to-day commuting and slugging out honey-do's on the weekends it's tough to beat an EV for reliability, convenience and economy.

Which EV is for you?

The first observation I had starting out was that there is really very little formal written documentation on building electric cars. Ford Ranger EV GM EV1 EVThis is largely because there are virtually no two alike, both in electric drivetrain and chassis used. Currently your only option to buy an electric car is one that's been converted by someone else, or buy a Solectria converted new Geo Metro (built in MA) for $30K or so. In selected areas you can *lease* a GM EV1 coupe or a Ford Ranger EV, but it's such a narrow market segment I don't think it's worth mentioning. I only count road EV's, there are a lot of folks out there that think some of these golf-cart sized Neighborhood Electric Vehicles (NEV's) are adequate. In my view, if you can't drive it on the freeway it's not a real EV. For those of us in the trenches, the process for either selecting a vehicle to buy (there are forums for buying/selling used EV's) or building your own starts with determining what the vehicle will be used for. Most Americans drive less than 30 miles a day, which just about any EV will do easily. Th!ink Neighbor NEV Bombardier NEVThe goal is to tailor the EV (or select it) to meet the average daily mileage needs you have while performing the job you need to do. For long trips you have your gas car, rental car, airplane, etc. The chassis (car or truck) you pick, battery sizes and types, motor size, controller size, etc. will all be based on what this vehicle will do on a daily basis. You can't haul tree branches to the dump in a VW bug, or fit a family of 5 in a small pickup. You also need to be realistic in your range requirements. It's easy to say at the outset "I want all the range I can get" but there are downsides. Range equals pounds of batteries.  The more batteries you have the further you will go. But the more batteries you have the *slower* you will go, and the bigger (and more expensive) motor and controller you will need. Costs of building the EV come into play too, but not as much as the intended use. The individual component costs compared to the total package costs really isn't huge between different types of EV's. It's the functions and capabilities of those components combined with the right chassis that will make the difference between a successful and impractical EV.

Donor Chassis Considerations

OK, now that I've gotten all the philosophical stuff out of the way, here are the nuts and bolts. Converting a gasoline vehicle to electric power is the ultimate form of recycling. You are taking a polluting vehicle and changing it to a less polluting one, while at the same time extending it's useful life by keeping it out of the salvage yards for a while longer. It helps to pick a car/truck you love. You will know it inside and out and will touch virtually every aspect of it's construction. You will need to pick one you can get parts for well into the future, not some obscure foreign job that you have to scrap when you can't find a ball joint (or whatever) for it. Pick one that's in decent shape. If it's a gasoline junker, it will end up being an electric junker. Just making a car electric doesn't fix torn seats, shot brakes, rust holes and cracked windshields. S10 Battery Frames The hardest part of any conversion is the battery frames. This is why it's very important to know exactly which batteries you will be using way ahead of time, otherwise you will have no idea how to place the frames. Having a welder (arc preferred), or having a friend with a welder that knows how to weld is key to doing this economically. It involves welding the various brackets and boxes, and permanently affixing them in various spots within the chassis. Nuts and bolts are not acceptable, as they are prone to coming undone, have questionable crash integrity and don't have the required stiffness to prevent fatigue at other stress points. Because we're talking some serious weights here (the pack in my truck is almost 1400lb.) it's not enough to just set them in the bed of a truck, or in the trunk of a car. Motor Adapter They need to be adequately restrained by some serious steel, with the mounting points distributed with enough surface area to absorb impacts and vibration without fatigue or coming apart. The second hardest part is getting the motor to transmission adapter properly implemented. Not because it's a particularly tricky process but because auto manufacturers aren't necessarily consistent from model year to model year. It's virtually impossible for the adapter machinists to maintain templates and data for all the possible transmission models and combinations. Once the motor and batteries are mounted the rest is easy, and almost fun. The electricals are usually very simple, and the remaining supporting componentry is fairly standard and straightforward. There are incidentals like air conditioning, power steering, heat, etc. but they are usually never any more difficult than identifying the proper componentry to buy and installing it.

EV Drive Components

Advanced DC Motor There are limited choices for motors and controllers that are *proven*, and only a few more that are unproven. Stick with the proven stuff, the pat rule I follow is an Advanced DC, Inc. 8-inch motor for cars, an 9-inch model for trucks. You can't go wrong with those. The alternatives are 2X the price but not 2X the gain. For the low end of the motor controller spectrum I would go with a Curtis 1231, for the mid end I would use a DCP 600, for high end I would buy a DCP 1200.

DCP Curtis 1231CThere are others out there but are not commonly used and if they fail you have limited repair options, even under warranty. Batteries are a *hugely* debated topic, there are as many opinions on which batteries to use as there are different types of batteries. In my opinion, for real-world EV use there are only two choices, Trojan brand flooded lead-acid, or Optima brand sealed lead acid. Trojan T-105 Optima YTEach has their advantages when it comes to performance, capacity, cost and longevity, so only you can decide which of those features you desire, limited only by the size/type of your EV and the depth of your wallet. If you've got the big bucks you can get flooded NiCads but they need different care and charging considerations. No other battery technology is available today (to us in the trenches) for EV's other than these two (lead acid and nicad).

EV Sticker Shock

One thing that bugged me when I first got into pricing EV parts was that there *must* be a cheaper way out. The EV parts suppliers must be putting a big markup on this stuff, or that there is some substitute somewhere that will work just as good at less cost. Well, the answer is there ain't no free lunch. There are lots of electric motors, controllers and batteries out there but at the voltages and currents a road EV needs, the available selection narrows considerably. You hear stories of using surplus aircraft engine starters, forklift relay speed controls, Sam's Club marine batteries, etc., but even if they hold up past their maiden voyage, they're certainly not dependable or powerful enough to serve other than occasional fun trips. Walk into a Grainger or a Graybar store and start asking about 30HP DC motors, 500 Amp DC fuses, 50 kilowatt motor controllers and they'll just give you a deer-in-the-headlight stare. Street Rod White ZombieEV's are on the very edge of what is available, so be prepared to pay the price. The dealers that are out there are definitely *not* getting rich on the backs of us poor slobs doing conversions. While the prices are kind of steep, the good news is that failures aren't that common. With the exception of the batteries, the EV driveline can outlast several donor car chassis (hundreds of thousands of miles). So you pay a lot up front, but it's likely you won't spend anything in (electrical) maintenance or repairs for a very long time. This longevity also promotes high resale values because the parts don't lose much value over time. You can likely recover most of your (EV component) costs when it comes time to sell it, with the possible exception of the batteries.

Kits and Plans

EV Kit If you want to take some of the guesswork out of building your own, there are a couple of suppliers that sell "kits" that fit older Geo Metro's, VW Rabbits and S-10 Pickups. The kits you might see do not usually include battery frames, so that work is up to you. I'm not a big fan of these kits because you typically don't get exactly what you want, and you really don't save that much money over selecting the exact components you really do want. Plus, unless you're a fan of Geo's, Rabbits, or S-10's, the only way a kit would work out is if you wanted one of those vehicles specifically. But there is a lot to be said for having the knowlege and experience of those who put those kits together to help you through it.

Buying a Pre-Converted EV

Now, if you've gotten this far and your eyes are crossed and think all of this is beyond your capabilities, you can always buy a pre-converted (used) EV. There are numerous internet forums for buying and selling privately converted and owned EV's, here is a list to get you started:

EV Sale Sites (as of Oct 2001)

There's a bit of sticker shock in buying a used EV too, largely because of the parts costs (and value), plus all the labor it takes to convert a car. I have well over 500 hours invested in building mine, even at minimum wage that's a pretty good chunk of change. So don't look at it as a 10 year old Escort or whatever selling for ten times what the ICE version would, think of it as an EV you can buy for less than what it would probably cost to do it yourself. If it's a vehicle that you can easily get parts for, it's age isn't much of an issue.

EV Organizations

EAA Logo Whether buying or building, having a local Electric Auto Association (EAA) chapter in your area is a huge help in finding out EV information. I highly recommend going to those meetings to get to know some EV'ers and see their machines. While in my opinion the return on the EAA dues is somewhat questionable, it's currently the only national organization for private conversion enthusiasts. If you don't have access to the internet, or don't want to take the time to search for internet news about EV's, the EAA's Current Events newsletter might be of interest. See the organizations's website at:

The Electric Auto Association -

Recommended Reading

As far as formal published information there isn't much, but there's one book that's a must-have, whether you're converting yourself or buying a conversion. It's "Build Your Own Electric Vehicle" by Bob Brant. (ISBN #0-8036-4231-5) He goes into immense detail and explains the theory and the physics of EV parts like batteries, motors and controllers. It's not about *how* to build an EV (contrary to the title) but how they work. It's a great reference, I use mine all the time.

Bob Brant Book

Internet Info Resources

Clearly the best source of information is on the web. Type "Electric Vehicle" in any of the search engines and you'll get many thousands of sites to visit. It's a great inspiration to see what others have done and built for their EV's and a great way to share data and ideas. Here is a list of some of the better internet sites: (Compiled Oct 2002)

Another tremendous source of information is the Electric Vehicle Discussion List, an email forum that brings together hundreds of EV'ers from all over the world, who's combined knowledge is the sum total of all that is known about electric cars. There isn't a question you could ask that someone on the list doesn't know the answer to. Of course you need email to participate, but it'd be worth getting set up with an old computer and a free email account just for this alone.

Instructions and info on the EV Discussion List


Well, that's about it for the basics. Just like any other avocation there are many nuances and specialties you can concentrate your interest in, but for now this should be enough to get you started. EV's are a really fun hobby with a practical side to them. You can drive your hobby to work or to the store and is an instant attention-getter wherever you park. I ended up learning much more than I ever wanted to about high power electrical and electronic things, motors, batteries and such, but the more you learn the more you *want* to learn.

Mark Brueggemann K5LXP
1985 Chevy S10 EV
Last Revised October, 2002

Back Arrow
Back to the EV
Main Page
Back to the K5LXP
Home Page
OS/2 Warp
© 2002 Pane Relief Computer Services