How To Convert Your Car To An Electric Vehicle

Does the backyard mad scientist in you want to convert your gas guzzler into an electric vehicle (EV) running on 1.21 gigawatts? Whether you would like to invest in a daily driver or simply get some engineering and mechanical experience under your belt, an electric car conversion project presents some unusual challenges. All the trusty gasoline powered components that you know and love need to be retrofitted with electric substitutes. You will also need quite a bit of fabrication and welding experience to mount various electric motors to power your steering, A/C compressor, coolant pump, vacuum pump, and transmission.

Building on a Solid Foundation

Some of the newer conversions are very professional and well-engineered. The first 2010 Audi S5 with a Tesla electric swap recently made headlines for incorporating the Audi Quattro all-wheel-drive system and using the transmission housing to retrofit a custom gear reduction setup. Many other projects have been mocked up along the same lines under the theory of using a higher quality of EV parts to build more mainstream production quality autos.

Tesla Audi S5 -
Audi S5 with Tesla Swap

The concept sounds alluring by the sheer (0-60 in 2.7 seconds) power that these Tesla engines are capable of producing. Why spend $200,000 for a brand-new supercar if you can build something even faster from spare Tesla parts? The best battery pack on the market right now is said to be the standard Kia Soul EV, renowned in the conversion world for its 30kWh of power loaded in a comparably small 400 lb. package.

The primordial ooze that these conversions evolved from appears to have its roots in electric forklift motors and DC controllers. The hobbyists with lower budgets who were simply looking to build any old Frankenstein EV would experiment with this platform for economy reasons. It is a great testing ground for builders to get some grassroots experience before moving on to expensive swaps. However, on the opposite end of the spectrum, it may present more challenges when working with raw materials. Instead of figuring out how to adapt a factory production battery pack, backyard builders were forced to choose from a variety of batteries with mixed results. They would typically stack many lead-acid, golf cart, or high-performance sealed batteries with lackluster results.

The true difficulty with a grassroots EV build is obtaining the same level of power to reach top speeds and long traveling distances. This seems to be an impossible brick wall that builders are wising up to as they seek out deals on factory EV parts to streamline their projects. As more electric vehicles hit the streets and find their way into junkyards after bad accidents and even fender benders, the price for resource materials to build these projects will nosedive. Many luxury autos are built to virtually self-destruct with any impact and can be far too expensive to rebuild with manual labor when considering the special tools, parts, and welding knowledge needed. At this time, the cost for getting your beak wet with some backyard engineering is too high for many would-be racecar builders.

If you are turned off by the idea of raw engineering a vehicle with lots of guessing, gray area, and fabrication, an EV conversion kit may be just what the doctor ordered for that mad scientist in you. These kits provide everything you need to turn your classic Volkswagen or Porsche into an electric marvel. These cars are ideal due to their lightweight, rack and pinion steering, and simplicity. You will need to follow the steps below to prepare your car for whatever type of EV conversion you have in mind.

Basic Elements of an EV Swap

1. Your best bet is to find a vehicle with a manual transmission. This is because an electric motor has a continuous range of torque and does not need multiple gear ratios to create a smooth and consistent acceleration. Converts fix this transmission in first or second gear and have a consistent range of power at all times.

2. The next step requires the convert to gut his vehicle of everything gasoline-centric. This includes the engine, the exhaust system, clutch, fuel system, and with some discretion other components that you may decide to delete. These include accessories like power steering and A/C. Remove your radiator if the DC controller you plan on using isn’t water-cooled.

3. Couple the electric motor with the transmission by fabricating a custom plate that fits the bell housing and allows the two pieces to perfectly align. Make sure that your transmission and EV engine are aligned in the same squared position as the former drivetrain or they can get damaged even if there are subtle deviations. It is better to assemble them on a bench where things can be checked for fitness. There are many kinds of couplers for splined pinions and smooth to connect the shafts.

4. Build a platform to mount your DC controller. Mount your battery packs securely and wire everything together through the controller to the engine. Don’t forget to add some kind of blower to cool down your battery. Most hybrid and EV cars use a blower exactly the same as the one used for climate control but you can also install a micro air conditioner. These will cool down the battery more effectively and a lot faster than regular blowers, reducing the need to have it on at all time which will definitely cut down on power consumption.

5. If your system is already constructed for drive-by-wire, you need to figure out how to tap into that signal and send it to your new DC controller with a CAN bus processor in many cases. If not, you need to replace that throttle cable with a potentiometer.

6. Add additional electric motors to power your A/C and power steering pumps if you plan on keeping them. If you live in a cold climate, it is recommended that you also install a small electric heater pump to replace the water pump that was in your engine. A vacuum pump has to be retrofitted at proper PSI to power the brake booster of your power brake system.

Gas Cap Charging System
Retrofitted Gas Cap

7. For the sake of finesse, most people install a charging system that is retrofitted and wired where the former gas gap and filler tube were located.

8. A voltmeter is retrofitted into the dash as a replacement for the fuel gauge. This gives you a constant reading on the state of your battery packs.

9. In addition, a DC-to-DC converter is required to power the accessories by connecting all the fuse box items to this source and/or through CAN bus controllers. This may take some time to resolve if there are multiple cables for onboard engine management computers and other accessories that are on the same circuits.

10. You may manually reverse your vehicle by using the reverse gear. Other systems simply run the same gear in reverse with a switch. This is something you have to explore in detail for your particular project.

11. The only other EV specific element you need is a large electric relay called a contactor. This relay acts like other relays in bridging a circuit between your battery pack and the controller. However, this relay needs to transmit hundreds of amps and voltages ranging from 96-300v DC without arching.

12. Finally, you simply need to retrofit your ignition system to activate the contactor and accessory circuits when you turn the key.

Of course, these are just some basic principles for constructing an EV vehicle. The more you study and strategize based on the research of others using the same model or materials, the more wisdom you have to perfect your engineering.

Worth Mentioning

When you are working with electricity, you need to be extra careful. It is not recommended to retrofit the EV systems into vehicles with electric components that may short out with a surge if you are unsure about the components you plan on using. Onboard computers can complicate things if the engineering of the computer system is not straightforward and easy to retrofit with CAN bus controllers. Even using a multimeter on computer systems to test for resistance can blow microprocessors. The arcane nature of the electrical systems in your vehicle makes it easier to retrofit an older Volkswagen or Porsche with manual windows and lean construction. A basic EV conversion can be constructed for as little as $4,000 to $8,000.

Stay Humble

The best training starts with humbling yourself. If you humble yourself and invest the hours and hours of time in polishing up your knowledge on every gray area of engineering the swap before it’s done, you will save yourself time, money, and headaches when you hit the learning curve. By joining online communities dedicated to helping others convert their vehicles and investing in late-model plug-n-play setups that are easier to retrofit, you will reap the best results. Although it may be interesting to see what sort of gadgets you can build when left to your own ingenuity, the expression that you can’t reinvent the wheel often comes to mind in these situations. Other people have struggled to accelerate and innovate with the same limitations on materials long before you arrived on the stage.

The innovators in this field are typically people who have a history in racing or tuning petrol vehicles, coming across a new generation of materials to adapt. As with any car project, the entire experience should be fun and interesting along the way. If you are already bored with the concept, you should probably just lease an electric vehicle.

Author’s Bio

Myles -

Hey there, I’m Myles the creator of ScanToolCenter. After being a mechanic for a few years, I always had trouble with my car diagnostic scanners, so I decided to dive deep into the subject and research them. After a few years, I think I would consider myself an expert (a guru at least). When I’m not tweaking the blog, you can usually find me in the garage playing around with my car.