Electric Car Conversions

Back in the late 1990s I converted a VW Rabbit to electric. A totally low-tech conversion with a DC motor and lead-acid batteries but it became my primary transportation until I “escaped” to Central America in January 2002.

In those 20 years things have changed as have my living situation. I am considering another conversion. Here are my considerations.

  • My typical trip is 20 km round-trip and a long trip will be less than 40km.
  • If I need to go to Xela or Guatemala City I always take the bus or a shuttle.
  • I will soon have a PV solar auto-productor system so charging will be free.
  • As I run an eco-conscious B&B, having an electric car will be a bonus.

Why Not the Chinese Answer?

There are a lot of electric vehicles being made in China right now. The lower cost ones are less expensive than doing a conversion. They are probably great for relatively short runs (say 50-70km) on relatively level terrain. But, they have limited weight capacity and are pretty small. More important, they have limited hill-climbing capacity. On my typical 20 km trip I need to go up two very steep hills. Not long grades but probably steeper than a fully-loaded low-end Chinese EV can handle.

If you convert a gas or diesel vehicle to electric, you generally just replace the engine with an electric motor. Thus, you still have a 4- or 5-speed transmission in place. While little or no shifting is required on most terrain, having a low gear solves the steep hill issue. Add in the fact that replacements parts (except for the motor and controller) are readily available for the vehicle rather than a special order from China and a conversion makes the most sense.

What to Convert?

While you could convert most anything, there are some considerations:

  1. The vehicle is relatively light in weight so energy requirements are fairly low.
  2. The vehicle is not littered with “power-everything”. Power brakes are normal and easy to deal with but power steering, air conditioning and such are real drags.
  3. The vehicle has a manual transmission.
  4. There is space for the batteries.
  5. Is the vehicle common where you live. (I.e., will it be easy to get replacement parts?)
  6. There is an adapter plate available.

While one could make an adapter plate (to connect the electric motor to the transmission) if you are not a machinist or know a good one, you probably want to avoid having to make one. While it is just a piece of flat metal, a small error could destroy bearings in the transmission and motor or worse. While EV Propulsion is not the only place nor the cheapest, they do have a reasonable assortment of choices. It’s a good place to decide which vehicle to pick for conversion.

What Will It Cost?

For what I want, quite a bit. But, I think it will be worth it. Here are some SWAGS:

  • Adaptor place and related mounting stuff: $1000
  • AC motor and controller: $4000 (DC motors are about half this price but with the AC motor you get more efficiency and regenerative breaking.)
  • Batteries: $1500-$4000 (I want Lithium and choices vary from week to week.)
  • Misc. electrical stuff: $500
  • Vacuum pump system (for power brakes): $100
  • DC-DC converter (to get 12V for car accessories): $200
  • Charger: $200-$500
  • A car: $500 and up

When Will I Start?

The short answer is when we have our new parking area so I have space in the garage. But, I am shopping. For example, I just saw an add for a Volkswagen Parati which is a small station wagon on a VW Golf chassis. It’s relatively cheap — about $2000 — so it would be a good starting point — unless it has power steering.

For me, starting with the vehicle makes the most sense. It’s weight will help determine what motor to buy and the available space for batteries will determine what batteries to buy.