Build your own Electric Car!


Step 8: Other

Currently, the car is insured and registered, although the DMV is still requiring that I drag it in and PROVE that there is no engine in the car before they give me the emissions tesing exemption.

This car can go for 20 miles on a charge, and has a top speed of 45 MPH, the speed limit right outside my house. In town is all 25 mph anyways. My typical ride is 10 miles for going to work, grocery store, post office, etc, and back home.

If I doubled up the battery pack, I should be able to go 30 to 40 miles on a charge.

This project has cost me about $1200 total, including buying the car in the first place. If I would have done the machining myself, I would have only spent around $800 for everything. This car charges at my house through a renewable energy program. All electricity comes from wind, bio-gas, and other renewable energy sources.

I kept the back seat and can carry four people total.

The original driver and passenger airbags are completely intact and functional.

I mostly drive this car in third gear. Turn the car on - put it in third - drive. It's really that easy. There's no engine to kill, so you don't have to push in the clutch before coming to a stop. The motor has so much torque that I can pull away from a dead stop in fourth gear.

I still need to come up with a heater. (EDIT: Please see below) I think I will wear an extra thick coat and gloves for winter driving and have an electric defroster on the dashboard to keep it from frosting. The heat issue has been on my mind since the start of this project. The inefficiency of a gasoline engine is a blessing in a cold Wisconsin winter.

I did gloss over a few steps of this project.
I skipped telling you how many times I took apart, and put back together, the electric motor. How many times I lugged it back and forth to the machinist's. A friend and I were up til 2 in the morning one night fixing the control arm mount! Or how I had to literally shorten the motor because it was too long to fit in the car! But those things are for another story at another time!

I made sure to have an interlock, so I can't accidently drive away while plugged in. Make sure to have a nice big fuse inline of your main battery pack.

All the little challenges of a conversion like this are part of what makes it fun and interesting. In my case, I did a fair bit of experimenting of the best way to run the power brakes.

Winter Heat:
Sure, gasoline engines aren't efficient, but all that waste heat sure is nice in the winter. Since this car no longer has the original engine, it doesn't have the original heat either. The blower motor is still there and works fine for defogging the windshield.
Some EV converters remove the original heater core and replace it with a ceramic heating element that runs on their pack voltage. That sounded like a lot of work, and I was already sick of tearing apart the dashboard.

I already had a household (120V AC) electric oil-filled radiator. I just put that behind the passenger seat, and run an extension cord out the window to a timer.
The heat comes on automatically in the morning and heats up the inside of the entire car before I get in it.
The mass of the oil in the radiator stays hot for about 10 minutes or so after I leave. Most of my trips aren't any longer than that anyways.

I like that with this heat system in that:
1) I didn't have to buy a darn thing
2) The entire interior of the car is already warm - seats, steering wheel, everything!
3) This also helps keep the batteries warm.
4) All the electric power comes from the wall, instead of the batteries

The only down side is that if I am parked all day somewhere that I can't plug in, I don't have that same heat for the ride home. On the other hand, most of my trips are pretty short, so it's not the end of the world.

This heat system consumes about 5 cents worth of electricity per use.

One of the reasons why I chose this car to convert was that it has manual windows, manual locks, manual transmission, non-powered steering,pretty much manual everything - except the brakes. The first time I drove the car as an electric conversion, I found the brakes to be a little hard. (You CAN stop the car WITHOUT power brakes, you just have to push really hard!) It was just a low-speed test drive, but it was pretty obvious that I had to work on the brake system. Power brakes work on vacuum created by the engine. Without an engine to make the vacuum, the brakes just don't work the way they should. 
Some people say to find a different, manual, master brake cylinder and install that, or even just to punch a hole in a certain spot in the cylinder to convert it to manual. Neither of these sounded like great options. Really, I just needed an electric way to make a vacuum.
So, to start out with, I played around with an aquarium air pump, just to learn how the vacuum brake system works. After that, I starting looking around for a 12v air pump with a connection on the "In" end, so that it could be used as a vacuum pump. A friend of mine dug one up, along with an aluminum bottle that had a threaded connector already on it.
I connected the air pump to 12V+ power through a vacuum switch. The vacuum switch measures vacuum in the bottle - if there isn't enough vacuum, the switch turns on the pump.

Now the car has power brakes, just like it did originally, only it's driven by a tiny electric motor in a little pump, instead of by a gasoline engine. Compare this to newer versions of the Prius, where the air conditioning is driven by an electric motor. That way, you can have AC without the engine running!
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Ken Myers4 months ago

Thanks for posting! However, I need more range, top speed. I was thinking of EV for commute to work, 40 miles each way. The commercial models (other than expensive Tesla) do not provide this, tap out at 60-70 miles, like Leaf. I also like the idea of DIY and recycling/repurposing old vehicle. I'd really love to take an older car with a nice body style (IMO) and modify it to EV. I'm not auto mechanic, would likely look to pay for the mod, assuming it can even be done, to make a vehicle that can 70mph, range 100+ miles. Some cars I thought might work for this mod include: (1) any classic car with bad or no engine, like ford mustang or Camaro, (2) the Ford Probe (93ish), Mazda MX6 (also 93ish), or Mazda RX7 (also 93ish). We'll I guess listing every car I would be willing to use would take to long. I really think with the state of the world, limited resources, and too much rubbish in landfills, that retrofitting older cars to run as EV is really an awesome idea that more mechanics should develop into a highly reliable (and reasonably priced) mod. Rather than spending $30k on a new EV, I could see buying a used "shell" car for $5k or less, and then paying a mechanic $10k to modify it to an EV, and it still is half the price and better for the planet. If anyone happens to read this and know if this sort of service is offered anywhere, let me know.

jpayton2 years ago
Also does the electric motor produce any heat? Could you pump a little coolent through it then through the heater core?
bennelson (author)  jpayton2 years ago
No, the motor doesn't get hot.
I am trying to do this same project. One thing I was looking at was generating power. I know running an alternator only adds load. but what if you attached a alternator to the motor and hooked that output through a switch that was closed when you let off the gas. It wouldent add much resistance when its not generating and it would add braking force while generating power. My commute has a lot of hills. running 1 or more alternators down the hills would add a bit of power. What do you think?
wobbler jpayton2 years ago
You don't actually need to add an alternator to do what you are talking about.

A motor being turned also acts a a dynamo/generator when no power is applied. In regenerative braking, this generated power is fed back into the batteries to get more mpw (miles per watt).

Look up "regenerative braking"

There is also more information here, although it confusingly talks about "reversing the motor" and "the motor running backwards". This doesn't mean you need to physically reverse the motor direction in a car, but you use the back generated emf/voltage to charge the batteries using appropriate circuitry:

< to the article author: great effort and design! >
bennelson (author)  jpayton2 years ago
Yes! That's one of the few ways you could get an alternator to work for charging an electric car. Still, you need that alternator to output your battery pack voltage, NOT just 12V.

Also, I would rig up the alternator to activate when you press the brake, NOT when you let off the accelerator. (Could could have the brake light wire connect to a relay that activates the alternator for example.) There are LOTS of times in my car that I am driving, but not touching the accelerator. My car seems to enjoy coasting.
couldn't you rig up an alternator to charge the battery packs
No way. It'd use more power than necessary as an attempt to use it's own power to power itself. If you could figure out a way for Power Over Unity, then yes, you could, but otherwise no. I have actually made a POU (Power over unity) at home, it ran off of a 6v dc motor and powered an alternator (home made) which output about 8v... :) cheers
but the amperage would be lower surely, you can't get something for nothing
(removed by author or community request)
bennelson (author)  Justdoofus2 years ago
I'm amazed at how many people don't know basic science.

"Can't you just put an alternator on it so it runs forever without recharging?" or some variation on that is a question I get almost all the time!

It's usually well-meaning people who just aren't thinking about where the energy comes from.
jpayton2 years ago
Get a vaccume brake booster from a diesel car or pickup. Diesel engines have turbos that cause positive pressure in the intake rather than a vaccume so the solution is Hydro-assist brakes (excessive for the average 1 ton pickup) or electric vaccume pump. Check napa.
sanwal3 years ago
i see you have applied the motors on the front wheels, what about the rear wheels?
bennelson (author)  sanwal3 years ago
It's a front-wheel-drive car, so of course that's where the motor power went.

The rear-wheels are non-powered, just like on any other front-wheel drive car.

I suppose a person could convert a car to four-wheel drive, but it wouldn't be as efficient.
codsters13 years ago
Hi bennelson. I am very interested in making a EV car as a delivery vehicle for a auto parts store. I was wondering if I could come up and take a look at yours. My name is cody.
bennelson (author)  codsters13 years ago
Hi Codsters1,

If you are somewhere near me, I'd be happy to have you stop by and take a look.

I'll send a private message with details.
satcomguy3 years ago
i have been thinking about building my own electric or hybrid car for a while now. this site has nice kits but expensive: I am an electronics engineer. I was thinking for a heating problem to use the heating element out of a hair dryer or a toaster with a computer type fan so it it quiet. and if you build them smaller you can have independent temps at each corner of the vehicle. this will take a lot less watts than a ceramic heater which most small electric heaters for your house use 1500 watts.
If you already have an inverter couldn't you just plug the batteries to the inverter and extend the range?
bennelson (author)  jimmerforpoy4 years ago
How do you propose? An inverter creates Alternating Current from Direct Current. For example, it's a great way to run household appliances from batteries. You could even run your house off your car during a blackout. How would you extend the range of the car with it?
you said you were running the aquarium pump with a power inverter coming from the cars cigeret lighter thingy that has normal outlets, right? so couldnt you plug in the chargers to the inverter in your car and "extend the range" by charging it from its own motor?
bennelson (author)  jimmerforpoy4 years ago
The aquarium pump was only a short-term "proof-of-concept", later replaced with a 12V DC air pump. The inverter would have run off the car's original 12V battery, which is simply recharged with a 12V battery charger when the car is plugged into the wall. There is NO ALTERNATOR on this car. Even if there was, the additional power needed to run the motor with the drag of the alternator would mean LESS power in the end, NOT more. Please see:
excellent job! i only have one question, how much does it weigh? I have been working towards my own, but never thought about a forklift or palletjack motor. bravo.
bennelson (author)  muscletruck73795 years ago
I don't know! I haven't weighed it since the conversion! It does weigh more than it did as gas. Not too much though, brakes work fine even with the power assist turned off. I keep telling myself that I am going to take it down to the local landscaping place and weigh it on their truck scale.
bennelson (author)  bennelson4 years ago
I recently weighed the car. It's almost exactly 2000 pounds. That's 270 pounds more than it did when I started. Another way to look at that is that its the weight of two medium-sized passengers. Convert the car from a four seater to a two-seater, and everything is PERFECT!
makenakai4 years ago
great job.   have you thought about hub motors?  go to and search for dc hubmotors.   they are sealed, efficient, cheap, and powerfull.  saves alot of hardware. also check out lithium batts.
If your going to look at lithium batteries then look at lithium polymer batteries.  Very nice power density and discharge rate.  Only downside if they are fickle about minimum charge levels and maximum discharge rate.  I use them in my experimental electric plane.  I can fly around on them for about two hours with a full complement of batteries and a full charge.
ewitwins4 years ago
Very nice! However, have you ever considered slapping a shaped photo-voltaic cell on top for a trickle charge? Y'know, for while your at work?
Carbaugh5 years ago
I'm a bit of a gearhead, and this is a wild experiment. But I was just going to say I believe Summit makes a vacuum pump that could be run off of a pulley. In a drag car with a High lift, wide lobe cam it kills the vacuum, so guys run a pump to keep their power brakes. Just an idea dood.
32voltman5 years ago
Some of the conversions I've seen take warm air from the cooling fan on the electric motor to assist heating in winter. Well done project. I've been gathering parts for myself for a year now. You have given me a boost to get going! Jim
matroska5 years ago
I too think of making such a pimpin' ride! (green is the new pimp, yo!)
Davvik5 years ago
I love it, It's people like you who are going to save our planet. Keep on makin' everything around you green. I wanna start one right now, I'm gunna make a parts list!