How to Build EV Car
Build your own electric vehicle (EV). To get started, this overview will describe the process to modify a compact car to create an electric vehicle. This vehicle will allow you to drive every day without using gasoline or being subject to the expense/price fluctuations that make the news every few years.
- Difficulty:
- Challenging
Instructions
Things You'll Need
- Torque wrench
- Channel lock wrench
- Cable crimpers
- Welding equipment
- Engine crane
- Bolts (at least 1/2 inch thick)
- Pancake motor
- Taper-lock hub
- Engine mount with associated spacer specific to your vehicle
- Motor controller
- Regenerative breaks
- DC-DC converter
- Battery charger
- Eight or more 12-volt lead-acid batteries (or lithium batteries, if you can afford them)
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1
Make sure that the car is in a position where it will not roll and where you can remove and install parts. Start by removing the battery, air filter and carburetor, engine, exhaust system (including the muffler, catalytic converter, and pipes leading to it), ignition system and alternator, engine, cooling system (including the radiator) and the fuel system (including the gas tank, fuel lines and fuel pump). Clean off any rust spots and spray with a rust-prevention spray available at an automotive supply shop. Remove the engine only after you chain it securely to an engine crane, since it is too heavy for a human to lift.
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2
Obtain a pancake motor (a "flat one" like those used in forklifts) or another suitable motor with a power-to-weight ratio that you find acceptable. You might save money by buying a used forklift for the motor and selling the rest of the forklift (along with any parts you took from your car that you didn't sell) to a scrapyard.
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3
Obtain a hub that you will use to connect the motor to the flywheel. You can buy one for an electric vehicle online, but make sure that it has a taper-lock fit, which is the standard for high-RPM vehicles (motors with a high number of revolutions per minute). Once the hub snaps in place it can't be removed, so do not snap it in until the motor is in position and the fit on the motor mount and spacer ring have a verified fit (see Step 4). Affix the hub to the motor but not onto the flywheel, yet.
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4
Buy a (1/4-inch steel) motor mount and spacer (individually or as part of an EV kit for your specific vehicle). Make sure the motor mount and spacer fit the transmission case, have a central hole for the motor to mount on the flywheel, and fit any necessary bolt holes and any dowels that need to stick into the mount. Bolt the spacer ring and motor mount on and see if the motor fits. If the motor fits well, snap the hub over the flywheel tip. Weld the spacer and motor mount in place, since they will come loose if you don't do this. Check the bolts on the motor periodically, and use lock tight to keep the motor in place. If it comes loose, you may have to use small welds to keep the bolts in place.
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5
Mount the motor controller so that you can use it to control the power to the motor. Some people rig this up to a foot pedal in the floor to mimic a traditional gas pedal. I suggest that a large foot dial might be more appropriate. This dial should be spring loaded like a mousetrap arm so that the spring spins it down to the lowest possible setting (zero) if your foot comes off of it. If you set the dial so that the power can go in reverse, you won't even have to shift to go in reverse.
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6
Install regenerative breaks according to the instructions that come with them from the manufacturer so that your car not only has a breaking system, but also recovers power as it slows down using the resistance to recharge the batteries. Do not remove the emergency brake. Test the brakes before taking the car for a spin, and have an expert help you.
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7
Attach a DC-DC converter and standard battery recharger to the frame in places that are accessible and at the same time out of the way so that space is available to put the bank of batteries under the hood. This DC-DC converter changes the voltage from the huge bank of batteries so that it will make a standard 12 volts in order to power the standard accessories in the car like the radio and the electric windows. The battery charger is what you use to plug in the vehicle at night to charge the batteries for the next day of driving.
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8
Put as many batteries as possible under the hood so that they are upright and easy to access. Any 12-volt lead acid battery will do, but lithium ion batteries are favored by some enthusiasts with deeper pockets. Wire the batteries in a series and hook them up to other parts you have installed using heavy-duty welder's cable. Use extreme care to to not get electrocuted. The DC-DC converter should be wired to its own battery so that you don't feel a change in power when you turn on the radio.
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1
Tips & Warnings
All the parts are available at EV parts dealers. Some of them come in kits, which greatly simplify the process.
Have an expert check all of your work before trusting your life to this complex project. Be extremely careful with electricity since one mistake will take your life. Electricity can arc if you get too close and you are working with a lot of power. Do not touch any electrically charged surface, including, but not limited to wires, terminals or any other conductive surface touching the high voltage or close enough to it for arcing. Install a plastic shield over the batteries and any other "hot" places to prevent mistakes. Avoid driving in wet conditions if any part of the conductive surfaces are exposed. Cover all metal and electrical surfaces with rubber tool paint (careful not to let the electricity travel though the wet paint). Do not trust the batteries to be predictable, and always proceed with caution. Make sure that the brakes work well before driving the vehicle. Standard brakes will not work unless you hook them up with special modifications not mentioned here; you are relying on regenerative braking combined with an emergency brake.
