Introduction: How to Build a 72 Volt Electric Vehicle – Car / Jeep


1. The first video shows the common components in an EV.

2. The second video is the Jeep as it is now with the Direct Drive.

3. The third video is the original Jeep with the Chain drive, notice how loud it is.

I decided to build an electric car. What car should I use, what motor and what kind of batteries? I started my research by viewing many Electric Vehicle (EV) builds. I also had some experience when I built my Electric Motorcycle (Instructables All this gave me and idea of what I wanted to do. I hope to add to those who have gone ahead of me and built, shared and motivated me to build an EV. This is how I went about building this Electric Jeep.

Step 1: Alternatives, Warnings, This Build and Get Organized


Don’t forget there are brand new EV cars that are coming out that will cost you a little more than $20,000 after all of the incentives. They will be engineered to a higher degree that most people can get close to at home. If you are here you are probably a tinkerer and may want to play with this technology. If not these cars are a great choice.


This is a project that can be very dangerous as you are working with high voltage and amperage. Be careful and learn as much as you can before you start. You should understand what you are doing so read and ask questions. Be careful with any EV project as no project is worth your life.

This Build

This build is a 1942 Ford Jeep. I like the look of these Jeeps and thought it would make a neat EV for local driving. It is not very aerodynamic so this vehicle would not make a good vehicle for driving on the freeway or at high speeds. This is a 72 volt EV which includes 6 - 12 volt Lead acid batteries. I wanted an older vehicle without power steering, power brakes and as simple as possible to work on.

Get Organized

I started a folder on my computer called ‘My Jeep’. I created a document to store all of my links that I thought would be helpful. I also started a document that had parts list from other EVs that were similar to what I was building. I also downloaded pictures of EV I liked. Then I started another document with my parts list. At this point I had a clue of what I wanted to do and how much money I wanted to spend.

Step 2: Research

First you must know what you want to build. Here are some of the questions you should be asking yourself. What do you want this vehicle for? If it is to go to the grocery store and back you may not need to go above 35 or 45 mph. You may want to use this vehicle to commute to work which may need higher speeds and longer distances to travel. This will give you the information you need to know about the vehicle. How far you need to travel and how fast you need to go. My point is knowing the speed and distance you have to travel will give you the specifications you need to build an EV. My job is about 3 miles away from where I live. My budget is around 3k, this is the cost of a low end used car.

Now start your search on the internet, EV Forums and Google - EV builds. This will give you a good idea of what people are doing. Each time you view one of these builds you may learn something. Start a document with links and pictures of things you like. You will see many VW Bugs, Motor Cycles as well as Smaller Cars. The reason why you see so many VW Bugs is that it is a light vehicle without power steering, power brakes and there are many EV parts available. This was my second choice and may be a car I build in the future. Consider these types of vehicles especially if you are not mechanically inclined. The EVs that are most commonly converted will have the most articles/forums that may help you get past a problem others have already solved. Many sites want to charge you for information that is available for free. You may want to buy a book on how to convert your car to electric and if you do buy a book that is recommended by many others.

Here is a list of sites I liked or had some good insight to building an EV. - Many builds and specifications - My favorite EV’s bike build (I used an Alltrax controller, use the site for your controller)
Sites I used to purchase items for my EV Inland Empire Driveline

I used a site named to get the parts list I wanted as they did all of the work for me (see ). They have kits that list all of the parts that go together.

Step 3: The Big Five

This section is to give you a starting point, you may already have a car and that section will not cost you anything or you may want to start with an old Corvette and you will have to pay more. This is to give you an idea of how much you may need to spend.

1) Car – Plan on spending around $1500 for a car in good condition that has a blown engine or engine problems. Consider your needs as mentioned in the introduction. Look for a solid car a good frame, brakes, tires up to date registration, pink slip and anything else you can think of. Get a checklist from the internet if you need it.

2) Motor – Plan on spending between $400-$3000 depending on if you want a new or used and other variables. The two big choices are AC or DC motors. Do you research to decide what is best for you. Do some research to decide what motor you want to use. I originally picked the Perm pgm 132 because my car was so light and I have no hills in my area. It was under power and burned up after a short while. I then got lucky on craigslist and got a WARP 9 motor. I started searching eBay, craigslist and any other site that showed up on my google search for the motor I wanted.

3) Batteries - Plan on spending between $100 – many thousands. I think you have basically two choices Lead Acid and Lithium. Price may be a limitation for some as the Lithium batteries can get expensive. All the battery types will have different choices within each selection. Lithium batteries may need special chargers. I choose Walmart Deep Cycle Batteries as this was within my price range and met my needs.

4) Controller – Plan on spending between $400 - $2500 again search eBay you may get lucky and find a good used one. Don’t forget you are taking a chance when you buy anything used as you don’t know how hard it was used and how long it was used. You need a controller that matches your motor. I chose an Alltrax 7245 Controller. There are different controllers for AC and DC motors so it is easier to decide on your motor first and get a controller that match that motor and for the voltage you want.

5 Other stuff- The other stuff you will need you will probably have to buy new. These items include charger(s), fuses, diodes, contactor, throttle, wire, wire lugs, nuts and bolts. If you have problems with your donor car you will have to fix those items also. These items will cost you around $200-$500.

Step 4: What Voltage EV Do You Want to Build?

When deciding what voltage EV to build there are so many variables that I could not possibly list them here. The batteries are the first variable. Most EVs are going to use a variation of two types of batteries. They are Lead Acid or Lithium. Each battery has so many variations. Lead Acid will be cheaper and more available. I use Deep Cycle Lead Acid Batteries. Some variations are Spiral, Glass Matt, 6, 8 12 volt and much more. They have many types of chargers for these batteries. Then you have Lithium which if you want lighter weight and longer distance you may want to use Lithium batteries. I would like to use Lithium batteries but they have not got to the point I can afford them yet. If you want to use them do your research as prices vary and so do the types of Lithium batteries. It seems that many people choose between 72 and 144 volt battery packs.

Step 5: My Stuff

1942 Ford Jeep $ 700
Parts to get the Jeep safe to drive (brakes and stuff) $ 200 Car Parts Store
WARP 9 motor $ 800
Controller Alltrax AXE 7245 w/400 Amp fuse $ 400
6 Deep Cycle Batteries plus core charges $ 492 Walmart
Driveshaft $360 Inland Empire Driveline
Major components Sub Total 2,952

Spicer 1350 Series Yoke $ 56
Albright SW200 Style Main Contactor - 72 Volt $ 85
Curtis PB-6 0-5K Ohm Throttle $ 89
Emergency Shut Off Switch $ 15 Harbor Freight
3 Amp Diode $ 4
1K Ohm Resistor $ 4
Reverse protection diode $ 2 Local Electric Parts Store
Key Switch $ 16 Local Electric Parts Store
Wire 3/0 awg 26' $ 50 Lowes
26 x 3/0 awg Wire lugs $ 28
Steel tubes, angle iron and scrap steel $ 100 K&H Metals
Inline fuse holder $ 5 Pep Boys
Chargers $ 150
Miscellaneous stuff $ ??? Misc
Total $ ???

Step 6: Mock Up, Pre-Build and Order the Parts

I gave you my list of parts and yours will be similar as most EV’s will have the same basic parts. You probably will have a different motor and so on but you will have a motor. Now that you have your list of parts you should mock up where everything goes. You should find out the size of your parts and use that to help with the mock up. You need to know where everything goes so you can order the right amount of wire. Setting up the engine and transmission may be important but the space used is normally less than the automotive engine. You will need to find a space to fit the batteries. You will want to make sure the batteries on your parts list will fit. Some people will use the back seat others will fit it in the engine compartment. Some choose to use the lithium batteries as they use less space for the same power. The reason you should mock up your EV at this time is to make sure everything will fit and you have a place for everything. If you want to build a 144 volt EV with 12 Deep Cycle batteries and you want to fit it in a Smart car, good luck finding the space. I have seen people use cardboard to do this or you can draw out all the parts and your EV on paper to see if everything will fit.

At this time you will need to de-ICE your vehicle. De-ICE stands for the removal of the internal combustion engine (ICE) and related components such as tail pipe, radiator and so on. This was already done for me so I had nothing to do. Think ahead when you do this. You probably will want to keep many components as they are needed on your EV also. The transmission, horn brakes lights and so on will need to be saved. Remember that if you have a simple car that does not have power brakes and power steering you will save some time as these components take special consideration and knowledge/research.

Order the parts
If you know all your components you will feel better when you do this. You should have completed your parts list, mocked everything to assure it will fit. Like I said earlier, some parts are designed for specific voltage. Now start your searching for the best price for the parts you need. The first thing I found was the motor I wanted on eBay. I was very lucky to find the motor with only an hour of use. This original motor burnt up because it was under powered. The next motor took months to find for the price I wanted. This motor I found on Craigslist. When you buy used parts there is a chance the parts may not work, when buying from eBay try to buy from sellers who have sold a lot and have very high percent of positive feedback and find out if you can get a refund if it does not work.

Step 7: My Biggest Mistake.

This build was a live and learn, I want to mention my mistakes so you can learn from them. The first build was a custom transmission and it would have worked if I had a more powerful motor. I think I still would have rebuilt it the way I have it now because the new build is so much quitter and have fewer parts that can break. A picture speaks a thousand words so look at the picture of the original design vs the new design. Like I said the original designed worked but was louder and the motor was too small. I increased the size of the motor and went to a drive shaft shop who built the driveshaft to my exact specifications. The Inland Empire Driveline Shop was very knowledgably and also advised me to add the adjustability to the drive shaft. This allows the motor to be locked in place and the rear-end to move up and down and the drive shaft can absorb the slack (pretty cool). Like I said my biggest mistake was the motor size, it was just too small. It got very hot after I used it and eventually heated up so hot that the solder was spitting out of the motor and the motor seized up.

Step 8: Pre-Build, Build and the Electrical

If you are going to use the cars transmission you will need an adapter plate to hold your motor to the transmission. So you should have included it in your parts list. This is where it is handy to use popular components. This is where all your research will come in handy. If you are going to use your transmission you need to decide if you want the clutch or direct drive. You should start with a diagram of how your parts work together. Most likely the controller schematic will show you everything you need for the electric components. The drive train components will probably be in the same place as the old drive train, so keep the bolts and nuts as you can reuse them. The more you are mechanically inclined the easier this is. I do not have a lot of experience building a car from scratch and I was able to do this. I tried using a chain drive and it did not work. I later used a drive shaft that directly connected the motor to rear-end.

I wanted the motor in line with the yoke on the rear-end. I used a string to try to make this a strait as possible. This was not that simple, I had to put the motor in place many time during the mock up to get this right. I welded new motor mounts and place it in the vehicle. I put the motor in place and attached it to the motor mount. The new motor was very heavy so I had my boys help me lift it in and out of place. Once the motor was placed I added the driveshaft and that’s it for the mechanical components that I added. I also fixed the brakes and did some other maintenance on the Jeep, it was originally built in 1942 so it needs some TLC.

I bought an Alltrax controller and it came with a fuse. On the Alltrax web site I found a schematic for the controller the Curtis PB-6 0-5K ohm potentiometer. The contactor needed diode and resistor so I bought them. I also knew I needed a reverse protection diode from the schematic so I ordered all of the parts that I needed at once. Basically your controller’s documentation will give you the plans to wire your EV. Depending on the voltage, the wire and wire lugs will have to be thick enough not to melt. I found this information on many web sites. I do not want to make light of this part of the build as it is dangerous and could be expensive if you wire it up wrong. Use the help from your controller’s web site and the site you buy your electrical supplies. I don’t want it to sound easy, it is very helpful if you can read the schematic or have a friend who can. I had some basic tools and a multi-meter. I soldiered all of my connections and used heat shrink to make it look nice.

Step 9: The Charger(s)

Based on the types of batteries you have you must have the correct charger. For Lead acid batteries you can get a single charger or a charger for each battery. I chose to have a charger for each battery, this will keep each battery at its best performance. If a charger goes bad you can replace just the one charger at a much lower cost. My cost was $25 each and the charger has the ability to maintain the battery and charge at 3.8 amp. This works perfect for my situation.

Step 10: Drive It

This is what it’s all about. Make sure you are prepared with a fire extinguisher just in case. It’s less expensive to have a burned up battery then a burned up car. I have AAA just in case I run out of juice or it breaks down. Document and create an Instructable so others can learn from you.