by
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.
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.
This
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.
The 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.
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.
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
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.
There 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.
Each 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.
EV'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
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
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 - http://www.eaaev.org
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.
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
http://www.madkatz.com/ev/evlist.html
Conclusion
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
![]() Main Page |
![]() Home Page |