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Tools to Have on Hand

Basic mechanic's tool set (metric & SAE)

Floor jack & jack stands—get high-quality ones, your life depends on them

Creeper—for easy access under the car

Portable engine hoist (borrow or rent)

Volt/ohm meter

Wire and cable cutters & crimpers

Manufacturer's shop & electrical manual for donor car (priceless!)

Resealable plastic storage bags, notepaper & permanent-ink pens—for bagging small parts with a note describing where the parts go

Camera for taking "before-and-after" photos of everything

EV Battery Banks

Choosing a battery type and size requires answering several questions:

• What voltage does your motor and controller require for optimum operation? The AC motor/ controller we used operates between 144 and 336 volts. One conversion kit provider recommended a 144 V battery bank (twelve 12 V batteries in series), but another strongly recommended 156 V so the controller would not cut out when voltage sagged under load.

• How much weight can the donor car carry? Stay within the gross vehicle weight limit, including passengers and cargo. Exceeding the weight limit can damage the axle bearings.

• What is the weight distribution fore and aft?

Heavily weighting a front-wheel-drive vehicle to the rear is probably not a good idea. Consider staying close to the stock vehicle weight distribution or about 50/50 fore and aft.

• How much room do you have? Many EV conversions have batteries mounted above the motor in the engine bay, obstructing the view of the motor and other drive components. For educational purposes, I wanted to be able to show off the electrical components, so I specified a smaller battery pack to meet the decreased space available and weight limits.

• What range do you want between charges?

Although most people want as much range as possible, I purposefully sacrificed range to stay within the original gross weight and not have batteries in the engine bay. I also intend to upgrade to lithium ion batteries in the future, which will improve range.

• How much battery maintenance are you willing to do? Flooded lead-acid batteries are the least expensive type of battery but require vented battery boxes and regular maintenance, such as adding distilled water. Sealed lead-acid batteries do not require active venting or watering but require more careful charging to avoid loss of their irreplaceable electrolyte. They also need a battery management system (BMS) to ensure equal charging or regular checks of individual battery voltage to discover any state-of-charge imbalance between batteries. Nickel metal hydride or lithium ion batteries also generally require a BMS.

• How much money do you want to spend initially and in the long run? While lead-acid batteries may be cheaper initially, lithium ion may be cheaper over the long run because the battery bank will last longer.

Installing Charger

the rear seat battery box top and reinstalled the rear floor carpet, seat belts, seat backs, and seat cushion.

At the end of January, I tested the Link 10 and set it for my battery's amp-hour capacity. I also tested the AC battery charger. With the new batteries at above 20% state of charge, the charger draws 3 to 9 amps AC.

Next, I installed the Azure digital motor controller (DMOC). In early February, I gave the car—still on jack stands—its first "test drive." I switched the forward/reverse switch to forward, made sure the transmission was in neutral, and advanced the throttle. The motor turned! I put the car in first gear and slowly advanced the throttle again. The drive wheels turned in the right direction!

Greg and I took the car off the jack stands and checked the fender well height at the rear wheels. It was 1 inch lower than the stock height before the conversion. I added 12 psi to the rear tires (Air Lift recommends adding 2 psi per 100 pounds of added weight, and we have 650 pounds of batteries), which reached the maximum 44 psi recommended on the tire sidewall. I also added 15 psi to the air shocks I had installed and could feel and see the rear of the car rise.

Then, the moment of truth—we drove the car out of the garage, for the first time in more than a year. But when I tried to back up by switching the forward/reverse switch to reverse and applying the accelerator, the controller cut out. The controller reset immediately when I released the throttle. I then switched to forward, and shifted the transmission to reverse, and the same thing happened. I suspected that the controller cutout was a max torque setting issue, which goes into error mode when the motor is starting to turn under load.

The next day, I took the car to town, avoiding the problem by driving the car using the clutch and first gear to start moving, and shifting up and down as needed. The EV drove just like an ICE car, with the regenerative braking acting like engine compression braking when downshifting. It was really nice to see the Link 10 meter voltage climb when decelerating, adding that energy back into the battery pack.

But there was still the issue of the controller cutout to solve. Canadian Electric Vehicles Ltd. e-mailed me instructions for using a laptop computer to capture motor controller data for Azure Dynamics to review. I set up the laptop in the car and recorded data with the car in first gear. As expected, the controller cut out. But this time, I had the data, which I e-mailed to Canadian EV. I received instructions back in just a few hours to change a setting in the controller. On another drive, we captured data on two high-speed controller cutouts, and sent that data to Canadian EV. In the meantime, I tried easing up on the throttle, which eliminated controller cutouts.

17. The Link 10 volt/amp meter: the EV's "fuel gauge," mounted in the dash for easy viewing. 18. Air shock in stock coil spring and tubing to air valve through trunk floor. 19. The AC charging plug. 20. Cruising at 70 mph during the highway road test. 21. An under-the-hood look at the completed installation.

I finally figured out that I'd been shifting up too quickly. Based on power curves I'd seen, the optimum motor speed is about 4,000 rpm. On another test drive, with a friend reading out motor rpm and amps from the PC display, I stayed in second gear until 45 mph (4,000 rpm), and stayed in third until 60 mph (4,000 rpm). The car cruised easily on a flat highway at 70 mph with no problem. There was throttle left, but I didn't try to go faster than that. The return route home from the highway includes a steep, 2-mile-long hill. I kept the car in second gear and came up the hill with no problem at 40 to 45 mph, the speed limit.

Later, I received more advice from Azure to change another setting. After making the change, I drove to town, ran errands, and came home without any controller cutouts. Success!

Once the car was road-worthy, I began monitoring mileage and charging kWh to calculate the car's energy use and cost. At our electricity rate of $0.028 per kWh, it costs about 25 cents to charge the car—about 1 cent per mile. That's pretty good, even compared to the original Echo's 40 mpg. For comparison, at the current $2 per gallon cost for gasoline, it would cost 5 cents per mile to run the ICE car. Last summer's gasoline price of $4 per gallon would have cost me 10 cents per mile.

Controller: The brains of the propulsion system, the controller adjusts the amount of energy sent to the motor based on input from the throttle potbox.

Potbox: Converts the motion of the throttle pedal into an electrical signal for the controller.

Motor: The brawn of the EV, a DC or AC electric motor converts electrical energy into mechanical energy to move the vehicle.

Transmission: Mounted to the electric motor the same way it would mount to a gasoline engine, the gearbox transfers power and torque to the drive wheels.

Main Contactor: The EV's main on/off control, this relay is often controlled by a standard key switch.

Instrumentation: The right meters are crucial to keeping tabs on your EV's performance. Standard are a voltmeter, ammeter, and an amp-hour meter.

Emergency Disconnect: This emergency breaker/switch automatically disconnects the battery bank in the unlikely event of a short circuit. The switch can also be used to manually disconnect the battery bank.

DC/DC Converter: Converts EV battery pack voltage to standard 12 VDC to run common automotive electrical accessories like the windshield wipers and sound system.

EV Conversion Tips & Tricks

• Subscribe to an EV e-mail list and don't be afraid to post your general plans and ask for comments and suggestions.

• Keep the car in its original condition until the conversion kit is received. That way, it's still functional while you wait—not just taking up space in your garage. Most importantly, you are more likely to remember how to put it back together.

• Identify efficiency gains. For instance, automatic transmissions are not as efficient as manual transmissions. Power steering is less efficient than manual steering mechanisms. Wherever you can reduce mechanical losses from motor-driven components, do so.

• Use ceramic core heaters instead of fluid heaters. Some tests show that fluid heaters take almost 10 minutes to warm up, whereas ceramic heaters get hot within seconds. A dual ceramic heater core is recommended for cold climates.

• Make a battery master plan. Batteries add significant weight to the vehicle, so try to distribute the weight evenly. Before my conversion, the front axle weighed in at 1,400 pounds and the rear axle weighed 980 pounds, for a total of 2,380 pounds. After the conversion, the front axle weighed 1,200 pounds and the rear axle weighed 1,520 pounds for a total of 2,720 pounds, still below the maximum gross vehicle weight (2,915 pounds) listed on the door post.

• Decide how active you want to be in managing your batteries. I decided to use sealed AGM batteries. Using a sealed battery means I won't have to be concerned about battery box ventilation, or have to water them. On the downside, a battery management system may be needed to ensure the batteries charge equally and do not charge too quickly, which can ruin them. If possible, use batteries all from the same production run, numbered sequentially, to ensure consistent performance.

• Measure the height of the transmission relative to the chassis. You'll need to duplicate this height with the electric motor installed to avoid binding the drive train.

• Consider removing the starter gear ring from the flywheel, since this will slightly reduce air drag inside the bell housing. Some people remove the entire flywheel, but I think it's best to keep it for smooth motor operation.

• Remember: You're working with electricity! Take precautions. While doing any wiring, turn off the main circuit breaker. A mistake here can result in injury, or harm components or tools.

• Fool the stock gauges. With no gas-tank sending unit, the gas gauge shows "empty", which is no problem, but the low-fuel light by the odometer flashed annoyingly. Checking the electrical shop manual, I found that a 50-ohm resistor wired to the gas-gauge sending unit would "spoof" the gauge to show half full, with no low-fuel light flashing.

• Pay attention to the motor power curves. The optimum motor rpm for mine is about 4,000. You'll need to tailor your driving accordingly for optimum performance.

• Check with your insurance provider. Our insurance company initially said they would not insure a conversion, but our track record with them over the last 40 years is excellent, so they agreed to insure our conversion for the car's book value, plus the value of the conversion. EV discussion groups can help you find an insurer if yours declines coverage.

On average, we use about 0.27 kWh per mile from the battery pack (0.3 kWh per mile from the outlet, due to charger inefficiency). The battery has a capacity of about 9.7 kW (156 V nominal x 62 Ah). If I discharge to 20% state of charge (SOC), I'd use 7.7 kWh. At 0.27 kWh per mile, the car should be able to travel 28 miles. Although this won't get us to the nearest large town, it's an acceptable range. (Most Americans drive 30 miles or less daily.) If I abuse the batteries to 0% SOC, the car might be able to travel 35 miles. But so far, our longest drives have been about 22 miles with 40% SOC left, and this meets our needs very well.

In the five months since we put the car on the road, we've put more than 2,000 miles on it. We use it exclusively for local driving and don't cringe when we make multiple trips to town in a day, since the cost per mile is minimal and we're using clean, renewable, hydro grid power for our energy source. We also have a 1.9 kW grid-tied PV system that typically produces more power each day than we use in the car. So you could say our car is solar-powered.

We've tweaked the DMOC settings a couple times to get optimum performance, and will install an electric air-conditioning compressor and electric cabin heat next. Overall, we are quite pleased with the car—you can tell by our "EV grin" every time we drive it!

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Randy Brooks ([email protected]) and his wife Anne operate Brooks Solar, a renewable energy business in Chelan, Washington.

Canadian Electric Vehicles Ltd. • www.canev.com • EV conversion components (Note: Azure Dynamics systems available through U.S. distributor Electro Automotive • www.electroauto.com) irSt

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