Build your own Electric Car!

The "Electro-Metro" Project.

Can't afford a Nissan Leaf? No Problem!

Build a cheap electric car yourself by removing the the car engine, replacing it with a forklift motor, and adding batteries.

I have plenty of videos about this project at:
http://www.youtube.com/user/BenjaminNelson
and 300MPG.org

The primary "build blog" for this project is at:
http://ecomodder.com/forum/showthread.php/ben-nelsons-electro-metro-build-thread-848.html
but watch out! That is a good read for when you have WAY too much time on your hands.

For a good intro to basic electric car construction, stick with this Instructable.

For more in-depth construction information, check out the instructional Video DVD available at 300MPG.org
If you are a teacher, and would like to start a class or extra-curricular at your school, I would like to GIVE you a copy! (Click this link for details.)

Step 1: Get a car.

The first thing you need to do is get a car. They are not all equal.

I was looking for something lightweight, with no power anything.

Heavier cars need more energy to push down the road, thus limiting your range on batteries.

Things like power steering and power brakes run off the engine, which is going to be removed anyways, rendering them useless. Power windows and locks add weight and complexity to the vehicle.

I ended up finding a Geo Metro for sale, for $500. The engine ran fine, and the body wasn't too bad, but I couldn't drive it home because the clutch was messed up. Oh well, this conversion isn't going to use a clutch anyways!

Make sure the car doesn't have anything major wrong with it (other than maybe a blown engine!) You want to do a Conversion, not a Restoration!

Comments

[msihcs]

First let me say I am extremely impressed that you would take the initiative to actually do this type of project I have dreamed of it but never actually took the leap.

My background is mechanical engineering (operating steam plants in the Navy) I do have a question though. My relatively average knowledge of electronics would lead me to think that as long as the motors are identical and the current to them is regulated properly that you could use 4 smaller motors (one at each wheel) instead of one big one to propel the vehicle. If run in parallel the motors should all turn at the same speed (I am sure a computer could further regulate the current to keep the wheels within a certain range of each other)

I ask this because the price of motors that are 25+ hp are a little high for the average person to purchase for their first EV project this (as BigTurd suggested) would also cut the need for a full sized transmission.

[phase90]

As Bennelson says, only two would be needed (not 4). There are additional issues with unsprung weight unless there are coupling shafts and the motors mounted on the frame. That would put a lot of stress on the suspension.
Second issue is synchronizing the two motors so they spin exactly the same speed (unless turning). If one spins faster (or slower) than the other, the car will pull to one side. Not fun. Dealing with tracking issues when turning due to a different turning radius on the wheels would be even harder. Better to drive a differential and let it do the work.

[bennelson]

Yes, in theory, each of 4 motors would only have to do 1/4 the amount of work. I used the existing transmission in the car because the vehicle is already designed to run as front-wheel-drive. The transmission not only has the gearing, but it is also the differential and connects the "half-shafts" (sideways-traveling short drive-shafts) to the front wheels. The trouble with using four motors, one on each wheel, is that you will have to figure out where to mount each of those motors and how to connect it to each wheel.



In a brand-new, custom-built vehicle, it would be easy to design for. In fact, with the motors out of the way, and no traditional transmission, it would give you great design flexibility. Modern car manufacturers talk about that sort of thing all the time. But for a simple conversion of an existing car, just replacing the engine with an electric motor and adding batteries is far more straight-forward than designing/manufacturing/fabricating everything for multiple motors and driven wheels.



I think that a four-wheel-drive hub-motor vehicle would be a great project to see. It might start off best as an "off-road-only" vehicle, something like a dune-buggy, ATV or something similar.



The "Tropica" electric car, designed by Bob Beaumont, also the inventor of the Citicar, was rear-wheel drive with TWO electric motors. Each motor was mounted on the swing-arm of the wheel, along with a belt and pulley to get the gear ratio right from the motor to the wheel. Also, each of the two motors had its own controller.

As for the cost of motors. There are plenty of good ones that can be bought brand new, specifically for EV use for $1000-$3000. That was a little expensive for my project, which only cost about $1300 total. My motor was from an electric forklift. I bought it for $50, cleaned it up, and installed it in my car. It works great.



For more information on repurposing forklift motors to power electric cars, please visit this link.

[Maker1721]

how fast does it go?

[bennelson]

Fastest I've gone in it is 73 MPH. Not bad for a forklift motor.

If you really want speed in an EV, check out the Tesla Roadster, White Zombie, or Killacycle.

[jbaker22]

would a starter motor from a diesel truck be able to get you up to 30 MPH if you put ball bearings on the rotor?

[bennelson]

No, starter motors are not appropriate for powering an electric car. They are physically too small, are too low-powered, are only designed for intermittent (NOT continuous use) and lack effective cooling.

[denhick]

thanks for the quick response,its nice to hear encouragement for a change. I will be at 7 springs in sept and look forward to meeting you.

[denhick]

Sorry if this posts twice, brand new member. Loved the e-metro. I have a 1978 26' carver (cabin cruiser) I use on the rivers here. my mechanic says the engine and outdrive are kaput. I think its time to buy some batteries and get started. No brakes, no power steering. Hows about you come to Pittsburgh for the summer, we start a friendship,convert her to D.C. power and expand our minds. No? O.K. how about some helpful advice? anyone?

[bennelson]

Once you get started in electric vehicles and learn the basics of batteries, motors, and motor controls, there's not that much difference between an electric car, motorcycle, or even boat!

I know several people with electric boats, and might be consulting this summer on converting our state university's sailing team flagship to electric drive. 

I made a blog entry on electric boats a while back you might want to check out. http://300mpg.org/electric-boats/

Since you are in Pittsburg, you might also want to check out the Mother Earth News Fair at Seven Springs in September. There are presentations on all sorts of great info, including several I will be giving on electric vehicles. http://www.motherearthnews.com/fair/SevenSprings.aspx#axzz2OvmtGPKe

[softenersreviews]

Thanks nice info really informative.

[softenersreviews]

wonderful Idea......

[bennelson]

New for this winter....
Heated coat!

The heated coat gives me instant warmth, and puts the heat where I want it - on me!

[Laisseraller]

Great Project Electric Car! I wondered if you ever thought of leaving the rear shaft on the electric motor enough to put a pully and connect to heavy duty alternator to run the car? you could build in a floater charger so you can recharge the batteries at the same time? Also changing gears while running must be a problem without a clutch?
If there was a way to leave the clutch you could shift gears while running. The electric motor was designed for slow heavy use not hwy speeds?

[bennelson]

There wasn't enough room under the hood to leave the tailshaft, it had to get cut off. Adding an alternator to an electric motor is the "perpetual motion machine approach" - you CAN'T get more energy out than you put in, only less.
Shifting without a clutch really isn't a problem. It's a very different thing having an electric motor that comes to a complete stop when you do (rather than an engine that has to idle) The electric motor has been working great.

[manish par]

hello i am from india and i have a design of car and want to make it and thinking of making and electric car and can u suggest me how to make a car of our own design pls. thanx

[greenenerji]

Converting our cars to electric best way for money saving.We must only choose the right material for our car.Electric motor , batteries, battery charger , speed control, etc.

Choosing electric motors working voltage is important and the batteries important.

If you have a car for coversion and you have money everything is ok.
But how to do ??? I am searching on internet.Articles , videos , there are lots of websites for it.

I have a skoda favorit 1300cc engine car.Converting it to electric can be better than using with lpg....

I found some seller that explains how to do it ? And which parts We'll use.

I was interseted in one of them.Explains good.... And cool )

It was Electric Conversion

[greenenerji]

I've forgotten to give link . I watched the videos than can be usefull for electric car conversion makers.

http://ozantavsan.evsecrets.hop.clickbank.net

[ride on toy dude]

i got hold of and old manual transmission, five speed lawn tractor. my dad was using the seized motor as a prop in a film and i decided to make it electric. now to my question. would you think that an 18 volt drill would be enough to at least make it go forward?

[bennelson]

A drill will be enough to make it go forward only if the tractor isn't carrying you or any batteries. Small motors like that have a lot of torque, but not long battery life, and the motor will quickly overheat.

You need a larger motor that can handle the continuous amperage required to ride the tractor around and mow the lawn.

My friend converted a gas riding lawn mower to an electric one. You can read about it at:
http://ecorenovator.org/forum/lawn-garden/161-ecorider-riding-lawn-mower-electric-conversion.html

[btahir90]

hello
i am an electrical engineering student from pakistan
i wanted to do this as my final year project.
could u tell me how much HP your motor was?
i meen whats your motor power in HP or kW?
regards
bilal tahir.
[e-mail]

[bennelson]

It is a 10.5 inch diameter DC forklift motor originally designed for 48 volts. I have usually been running it at 72 volts.

Cruising, it typically takes 100 amps, but I can pull up to 500 amps (accelerating, uphill) briefly.

72vx500 amps is 36kW or about 48 horsepower.

72V x 100 amps is 7.2kW, or just under 10HP.

[ride on toy dude]

i wasnt going to use it as a mower but instead completely remove anything related to mowing from the machine. hopefully that should shave 30 lbs from the thing. i want to use it as a transportation device. i also wanted to learn how to drive a manual on it since it is a 5 speed manual.

[ride on toy dude]

thanks!! i read his posts. would a starter motor work? i have one of those. it is easily twice the size of a drills motor.

[bennelson]

You don't want to use starter motors. They are only designed to run on 12V and only very briefly. You could use one of those on something like a light electric bicycle.

People have built drill-powered bicycles too. Just make sure to do the hard work of pedaling to get getting, then use the drill for cruising speed.

[ride on toy dude]

thanks so much. ill avoid using one of those.
oh, and my first ible was a drill powered bicycle.
i have also done the same with a razor scooter.
they were both friction drive.

[bennelson]

Cool, so that means you already know all the basics. You just need a larger motor and batteries for larger projects!

[CamStreet]

Hey Bennelson, Nice work you've done there :D I also plan on doing this sort of thing as my first car, however the distance you get has kind of set me back, although as a general question, would attaching an alternator to each wheel increase the distance you can travel in the car?

also is there any other way to generate electricity to maybe extend the range?

[bennelson]

My car was designed for a fairly modest range, with USED lead-acid batteries. Lithium batteries (or even NEW lead-acid) would give a better range, but at additional cost.

Adding alternators to each wheel wouldn't help. It would be crazy trying to do fabrication for the space and gearing needed for that to work. Even then, the alternators could only be active when you WANT to slow down! (As the alternator creates resistance on the spinning motor to create electricity.)

You COULD add solar panels to a car, but unless it is a very slow speed, boxy vehicle, with a large flat roof, it won't help much, but will add to your expense. (I do know of golf carts and electric pontoon boats with flat roofs, covered with PV panels.)

The simplest way to extend range (other than having more or better batteries) is with a range-extending generator. That's the route that I took when I converted this electric car into a Range-Extended Electric Car (sort of like a Chevy Volt) with a propane generator.

I made an entire Instructables on that, which you can see at: http://www.instructables.com/id/DIY-Plug-In-Hybrid-Car/

[kgross1]

Regarding the solar panels.
I was thinking that if you park somewhere that gets sun all day while your at work, you could use them to get some extra mileage out of the batteries while the vehicle is parked

[CamStreet]

Thanks for your quick reply :D

yeah, I guess, I did have an idea over the weekend tho, why not use the fuel tank to house extra batteries? that would increase range and save some space :D

[bennelson]

On this car, the fuel tank IS removed, and I cut a hole in the floor where the fuel tank was. I welded a rectangular metal box in its place to hold batteries. Works well.

[CamStreet]

yeah, I saw you removed it, just didnt know you put a box there, fair enough, how many extra batterys did you fit in there?

[bennelson]

5 batteries in there - Group 31 - 100AH capacity each.

[darris321]

So there's still no power steering?

[bennelson]

This car never HAD power steering to start with. That's one thing I liked about it for an EV conversion.
Power steering runs off of engine power. If you remove the engine, you need to somehow provide power to the power-steering pump. That could be an additional electric motor or a pulley off the tail-shaft of the drive motor.

Some cars also have both a manual steering rack and a power steering rack, and you could swap it out, but that sure sounds like a lot of work.

My Geo Metro retains its original manual steering. It drives and steers great.

[mjohnson72]

Thanks nice info really informative...video pool

[fireproofshark]

brilliant project, i have an old beetle and was looking into trying to adapt a similar power brake system into it do you have any pics of the finished brake system setup and what sort of vacuum pressure was required?

[bennelson]

Take a look at STEP 8 - OTHER, the last photo there shows the vacuum bottle and 12V air pump that I used. (There are two pumps shown, it's the one on the left that is what I ended up using.) I don't really have a good photo of "the finished brake system" as it's not all right next to each other under the hood. The main thing NOT shown in the photo in step 8 is the pressure switch.

It's a simple thing threaded onto a tee on the vacuum bottle with three terminals on it. The switch has a common, normally open, and normally closed terminals. I ran 12V power from the circuit that switches on, when I power up the car, to the pressure/vaccum switch. If it senses there isn't enough vacuum, the circuit is completed, and the pump turns on, pulling air out of the white aluminum vacuum bottle. When there is enough vacuum, the switch breaks the circuit, turning the pump back off. The pump runs for a few seconds right when I turn the car on, and briefly again about every third time I press the brakes.

I used an Airtrol F-4200-X30 switch, but anything similar should work fine.

I also have a simple one-way valve on the hose (cheap part from the auto store) to keep air from leaking back in, once it's been pumped out.

[P.John Paul]

Hi Ben,
This is John. I am a software professional. but i want to do something different from regular life. I read your artical. it is wounderful. I want to run my Matiz Car using Electricity. Can You help me to achieve this?

Kindly provide details about Motors and other items that are required to make the Daweoo Matiz Car as a Electric Car.

Is it required to charge the battery separately or is it automatically charged when we run the car?