RWD newsletter - April 2009

The E-Volvo: Converting my Volvo to Electric Power

By: Mike Ahern - ipd Customer

My name is Mike Ahern. I am a process engineer for a company called Solyndra, which makes solar panels in Fremont, Ca. I wanted to get to work without using gasoline. I live in West San Jose, about 16 miles from work.I started reading about electric cars and pretty quickly found people doing it themselves. It looked like fun and I thought I could do it. I found a company, EV America, which sold me most of the parts and helped me with a video, a manual and assisted with my many phone calls.

There were many people who told me I ought to use a lighter car, but I love Volvos and their safety. I will never drive another brand of car. I decided the added weight of the Volvo was a challenge. When considering adding 1000 lbs of batteries to a car, the structural integrity of Volvos make them great candidates for electric conversion. I have owned 5 Volvos and bought parts for all of them at ipd over the years. I decided the platform for my conversion should be a 240.

First, I purchased a donor car. I found a 1978 Volvo with a blown engine on craigslist for $150. It had a manual transmission and manual steering. I would have preferred manual brakes but all 240s had power brakes. In retrospect, 4 wheel disc brakes and power brakes are good for stopping a car that ended up 500 lbs heavier than stock after the electric conversion.

If you get a car with manual steering you don’t have to worry about what will spin the power steering pump. Every conversion I have seen requires a manual transmission. The coupler and adaptor plate I got used the existing manual transmission. I sent the clutch plate to a machine shop and they mounted the coupler right to it. I got a 12 V electric vacuum pump on ebay which supplies vacuum for the brake booster. My brake booster turned out to be leaky so I got another one from the Pick n Pull in San Jose. The replacement booster works great.

After towing the car home, I started removing things from the donor car, first the radiator, then the exhaust, then the engine.

The first new thing put into the car was the 9 inch dc electric motor, from Advanced Electric DC motors. The original manual transmission was mated to the DC motor with an adaptor plate from EV America. The clutch was removed, the shifting of the car is now done without a clutch. It is not a difficult process once you get the hang of it. Mostly I just use 2nd and 3rd gears.

The mount on the motor came from EV America, it was made for an S10 pickup. I had a sheetmetal company in Santa Clara, CA called Pega Precision make me the 1/4 plate steel mounts which got me from the mount on the motor to the mount on the car. ipd sold me new rubber motor mounts. So from the frame of of the car it goes: Volvo metal mount, Volvo rubber mount, Volvo metal mount, fabricated mount, S10 electric motor mount, motor.

Also from ipd I got the sway bar kit for front and back sway bars, the beefier rear springs, and new rear shocks.

There is a variable resistor box with a place to attach the throttle cable, I mounted that on the drivers side in the engine bay. The Curtis controller I mounted to the adaptor plate near the firewall. EV America sent a detailed schematic, which made it easy to wire everything up.

On the right of the picture (above right) is the resistor box. This box sends a variable dc voltage to the Curtis Controller, which sends pulse width modulated (pwm) voltage, 144V, to the motor, the duty cycle dependent on how far down I am pressing the accelerator.

With electric cars, there is a lot of current going through the wires, sometimes over 100 amps. So you need big wires. A neighbor had 1/0 copper welding cable he gave me and I used it for most of the cables. The lugs for the cables came from Grainger, and from work I borrowed an electric crimper which made great hex crimps.

For the battery boxes I used aluminum bar stock I got from work, and a lot of trips to Orchard Supply Hardware for hardware and various fasteners. There are four batteries in the engine bay and eight batteries in the trunk. The 12 Trojan T1275 lead acid batteries are wired in series, and there are 2 long cables going under the car from the front to the trunk. I mounted the long cables using the exhaust hangers.

The 144 V charger I bought from Electro Automotive. It plugs into a standard 110 VAC outlet, and turns itself off when the 12 batteries are fully charged. I drive around with 2 long extension cords, enabling me to get power from about 100 feet from the car. Once I got a charge from a plug in by a soda machine.

There is an accessory battery, which I got from the local pick n pull. It runs the lights, wipers, brake vacuum pump and the control voltage for the contactors and fans for the electrical components. I charge it separately with a 12 V charger. When I need warmth I use a hat.

To legalize it I had to go to the Cal DMV. First they sent me to the smog referee. Once the smog people had verified that it was all electric, I went back to the DMV and got it legalized. If I go back one more time, I can get a carpool lane sticker for the evolvo.

My daily driver is still a 1990 240 wagon, but as the weather gets warmer and the daylight gets longer I plan to drive the evolvo to work more until hopefully soon it is the daily driver. Supposedly if I am careful with the battery pack it will be good for 20,000 miles. In 2 years ideally the prices on lighter more exotic batteries like lithium ion will come down.

Results:

• Range: 35 miles between charges.
• 6 hours to completely charge 12 12V batteries
• Total cost to charge $1.32
• Top speed 55 mph.
• Total time from getting donor car until running all electric: 14 months
• Total cost for conversion: $8000

Major tools needed:

• Engine hoist (for removing old engine, installing new motor, installing batteries, 82 lbs each)
• Band saw
• Drill press
• Hand drill
• Voltmeter
• Crimper tool for battery cables

Sources:

• http://www.ev-america.com/
• http://www.electroauto.com/
• Silicon Valley Electric Auto Association: http://www.eaasv.org/