ProEV - Electric Imp Test Log #15

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Electric Imp Testing Log

April 17, 2003, Thursday - Testing Begins.
April 18, 2003, Friday - It's the batteries, stupid!
April 19, 2003, Saturday - Small Steps.
May 5, 2003, Monday - Keeping the Motor from Braking.
May 6, 2003, Tuesday - Slowing with Regenerative Braking.
May 8, 2003, Thursday - Better Regen.
May 9, 2003, Friday - The first test drive.
May 10, 2003, Saturday - Upping the Amps 1.
May 12, 2003, Monday - Upping the Amps 2.
May 13, 2003, Tuesday - Upping the Amps 3.
May 14, 2003, Wednesday - The pack is put on charge.
May 15, 2003, Thursday- Slow Going.
May 20, 2003, Tuesday - Battery Killing.
June 2, 2003, Monday - Onward.

June 5, 2003 -Thursday

Another battery bites the dust: Another test. This time the voltmeter is watching #133. It is reading 2.115 with no load, and 2.098 as soon as I switch on the system and the very light load of fans and electronics come on. The pack voltage was 375.4 no load, 375.1 on.

Amp limit is 75 total. The car is pretty peppy but the #133 sags alarmingly under full throttle. After 3 miles ( 1.030 Kwh), we decide to check whether the voltage sag is really a problem.

From a dead stop, I floor the pedal. Amps jump to and hold at 80. Torque hits around 390 lbf-ft, and drops. At the same time, voltage drops from 374 volts to 314 volts for 5.0 seconds. Then drops again as #145 reverses. The inverters shut down and the car rolls to a stop. The crew moves in to change another battery.

I roll out again without charging and two voltmeters to watch. One on the replacement battery, one on #133. I drive another 11 miles. The pack sags as low as 300 volts. Total Kwh used is 4.065. Up on the jacks, we discover that under our 4 amp load, pack voltage is 334, but # 127 drops to .98 volts. This can not be good for it!

We recharge at 446 volts (Constant voltage charge 2.5 volts per cell).

June 7, 2003, Saturday - Checking the charge.
June 10, 2003, Tuesday - Darwin thins the herd.
June 11, 2003, Wednesday - 10 mile run.
June 13, 2003, Friday - Getting the motors to work together.
June 16, 2003, Monday - Balancing the motor draws.
June 17, 2003, Tuesday - Align the car.
June 21, 2003, Saturday - One step forward, one back.
June, 2003 - April, 2004.

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