The Conversion Process

CLEAN CARS

To reduce the pollution from petroleum (fossil fuelled) transportation we must look at other energy sources. Hydrogen is promising but still many years away from consumer use despite billions of dollars spent on research. Electric power is here now and available. Unfortunately the big auto manufacturers (original equipment manufacturers OEM's) have discontinued their efforts to introduce battery electric vehicles (EV's). I feel that they have realized that the EV's do not meet the continual repair cycle that gasoline and diesel powered vehicles do with their ignition, fuel and emissions systems. Without continued repair revenue and low sales volume initially they are not interested. The components left in common are the complete body, frame, tires, brakes and perhaps the heating and cooling system.

There are four basic sections to an electric vehicle: a charger, a traction battery pack, a speed controller and a motor. In an electric vehicle the useful life of a battery pack is three to four years, the controller and charger will probably outlast the vehicle and the motor may outlive the owner. That in a nutshell is why I am interested in electric vehicles. This article is based on my experiences converting a Chevrolet S-10 pick -up truck (a work still in progress) and a small SUV for someone else as well as reading several books.


CHOOSING AN APPROPRIATE DONOR VEHICLE

The conversion process starts with selecting an appropriate donor vehicle. All vehicles could be converted. Most are either too heavy, not of a popular make (to obtain parts later) have an automatic transmission (some power lost in slippage) and some may be rusty. That leaves the popular, compact, standard transmission vehicle as a best choice. Since electric power has sufficient torque at low rpm idling is unnecessary. It is easy to do most "around town" in second gear.

Now that we have eliminated a lot of potential donors let us look at other criteria. Air conditioning can be run with an electric motor for the compressor but EV's are naturally cooler as there is no heat producing engine under the hood. I will be using a simple fan on the dashboard in my pick-up conversion. Commonly converted vehicles include VW Rabbits, Metro/Spring/Firefly/Swifts, Chevrolet S-10 and Ford Ranger pick-ups. A visit to the EV Album (www.EVAlbum.com) will show a large number of popular conversions. Another criteria is body condition. Rust caused me to abandon my first donor vehicle. It looked great at first but then time passed and the project was delayed by the necessity of making a living. I have recently obtained an identical donor that has little rust since it came from Vancouver, where the climate is milder.


DO IT YOURSELF OR PROFESSIONAL HELP?

Assuming we now have a proper donor we have a number of choices. We can do the job ourselves or hire the job out to a shop specialising in conversions. One such business is REV Consultants in Ottawa operated by Richard Lane. Conversion shops will usually supply the components to do the job yourself if you wish. There are two basic ways to proceed; one can buy a "kit" if a popular donor has been chosen or one can buy the parts separately and invest sweat equity. My approach is to hire out the jobs that are beyond my interest or capabilities. The most complicated part is the adaptor plate which mates the electric motor to the transmission. This requires very accurate machining since something that spins at up to 7000 rpm must be well balanced and very carefully aligned. I contacted this out to Rick Lane. Welding the battery boxes can be a problem if one does not have proper equipment but local welding shops should be quite willing to do the job.


ELECTRIC COMPONENTS

Alternating or Direct Current? These are two distinctly different systems that can be used. Most private conversions are DC but if one has a larger budget some AC systems are commercially available. AC systems require an inverter to change the DC power from the battery to the AC for the controller to send to the motor. However, more components means more cost; but one advantage with AC is regenerative braking which is built into the controller and saves wear on the friction brakes that normally stop the vehicle.

Charging the batteries can be handled several ways. Some people mount a charger in the vehicle, referred to as an opportunity charger, since it allows one to charge wherever there is access to electricity. This charger would run off a normal 15 amp, 110-volt circuit. The charge rate is fairly low but if one has lots of time this is fine. The second charging option is a 30 amp, 220-volt charger at home. Stove or dryer plugs can be installed in the garage for these chargers and can recharge the vehicle in three or four hours instead of eight or nine. Many just have one charger, but in my situation I have opted for two.

In common with most enthusiasts I will be using deep cycle (flooded) golf cart batteries. Mass produced they are widely available and will cost about $100.00 in Canada. Sealed lead-acid and nickel cadmium are also used by some. They are more expensive, offer slightly less range, but, less attention is needed and they have longer service lives. There is a lot of research into nickel-metal-hydride and lithium ion batteries since these chemistries store more energy for the same weight. They are becoming available. Greater energy density will mean more range for the same battery weight. Battery boxes are usually placed under the hood and in the trunk, or in the case of pick-up trucks under (or in) the cargo box. Since lead-acid batteries are most efficient at temperatures between 20 and 30 degrees centigrade, we should insulate and heat them for the winter. This makes the battery boxes larger than the ones our southern neighbours use. I am planning to build three boxes under the cargo box and hinge the box (dump style) for access. To avoid cold weather losses in the transmission, synthetic lubricants are used that offer good protection with thinner oil (lower viscosity). The OEM's are using synthetics in new cars now.

Since I have decided on a DC system I have a choice of several brands of controllers. Curtis Instruments is the largest manufacturer of controllers for both on and off road vehicles (e.g. forklifts). One advantage is dealers often have spares and used or rebuilt controllers are available. A newer manufacturer is DC Power with their Raptor series. I have purchased the Raptor 600 since it has several features the Curtis does not have. General Electric, Zapi and Auburn are other brands of controllers that are available as well as used units.

My motor is a 9" WarP from NetGain Technologies in Illinois, supplied by Rick Lane. Another popular choice is the Advanced DC motor designed originally as an oversized fork-lift motor. Smaller vehicles have similar choices available. General Electric also manufacturers similar sized DC motors, as do many others, however it is a wise idea to resist the temptation to use an aircraft starter motor in a road vehicle as these motors were not designed to take the higher voltage and heavy amperage draw.

Other components include heavy cable to carry the large current required to move the vehicle. The two-ought (2/0) welding cable is the most common size used. I am using Portable Power Cord that is used in the motion picture industry since it is rated for hard usage and high voltage. Contactors are the heavy-duty switches used to turn the vehicle on and off. Instead of gasoline, oil pressure and engine temperature gauges we have battery voltage and motor amperage. An E-meter is used to give precise readings on the battery condition. A tachometer is needed to help the driver keep the motor rpm sufficiently high enough to avoid overheating and also to make sure it does not rotate too quickly and throw itself apart.


A WORD ABOUT LEAD-ACID BATTERIES

The usable capacity of the battery pack is partly determined by the rate at which the energy is used, that is, if one uses the energy slowly more is available and if one is in the habit of accelerating quickly there is less 'fuel' available, just like in gas cars. Unfortunately, this effect is more pronounced in an electric vehicle since the available range is limited from the start and refuelling isn't a simple matter of pulling into the nearest gas station for a quick refill. Electric vehicles force the operator to drive more cautiously, planning stops and starts well in advance, all in the interest of squeezing the greatest range possible out of the vehicle. If everyone drove this way, the world would be a lot safer place too.


CONVERSION COSTS

The cost of a conversion project can vary widely. Used EV's are sometimes available and are often recommended as a good start and usually only need new batteries. I expect to spend about $12,000.00 Canadian on parts and labour for my conversion. I could do it cheaper using used parts, a smaller motor, and a smaller donor vehicle but that is not my style. The running cost for electricity should be less than $2.00 per day, which is much lower than an equivalent gas vehicle and helps to recoup the conversion cost. Sources for books and parts can be found at my web site www.ontarioEV.ca or at www.evsociety.com. Join your local EV club (or create one) for more information, buy an EV book or research the internet….and good luck with your electric vehicle.


by Neil Gover