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Old 10-28-2010, 04:56 AM   #3916 (permalink)
The Toecutter
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Join Date: May 2010
Location: Ghettoville, USA
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Rebellion - '16 KMX Framekit Custom electric velomobile
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I had thought the batteries were the problem at first; we found one bad one, removed it from the string, and tested the car on the lift with the bad one removed, starting at 24V and gradually stepping the voltage up. In the lift, with 156V, the ammeter read ~20A just to spin the wheels.

The batteries are flooded Exide Nautilus type.

The Arduino board gave no problems and the truck drove around fine on that using the same exact power stage setup.

Aside from one bad battery that he removed(it was originally 168V nom), all of the other batteries didn't even register a resistance on the multimeter(it only goes down to 0.1 ohm), while the bad battery registered ~6.5 kOhm. Removing the bad battery took us to 156V nominal. I then thought we had solved the problem.

Before the final on-ground test, their water level was fine, and the 156V pack was reading ~160V. We even checked all of the connections before running the truck off of the lift, along with the internal resistance of each battery.

When we used the ReVolt control board with the truck on the ground, it reversed back a few feet just fine. Forward in 2nd gear, the truck lurched for about 1/3 of a second with very light throttle and the IGBTs blew up. There was no spike in the ammeter reading(it probably didn't react fast enough). The batteries quickly gave off a smell of rotting eggs once the IGBTs blew. Acid/water sprayed all over the battery box.
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