With the winter weather setting in, I've sealed up the battery boxes with fiberglass and pink insulation as best I can. I made sure that all the battery warmers are working, and use them as needed. Similar to the PbA batteries, the back box is always the warmest, the middle box is next, and the front box the coolest.
I also noticed that my warning buzzer goes off if I punch the accelerator and hold it at 300+ amps for 5 sec. or so, even after a full charge. This didn't happen in the warmer weather, so I've been testing the batteries. I hooked up the multi-meter to each cell and note the resting voltage and the voltage when I accelerate and draw about 300 amps (close to 2C). I found the 'culprit' very early. In fact, I've not finished testing all 48 batteries yet. 1 battery drops to 2.4V at 2C! It's not supposed to do that, and since I have a couple spare ones, I'll swap it out in the next couple weeks when I get some time (it's not easy to get this battery out).
Another test was an endurance run that I just completed tonight (still have all the same batteries in there). I did 81 miles - a record! No heater running, so it was a bit chilly. About 75% highway driving, much of that against a stiff cold wind. I didn't accelerate too much. The warning buzzer never went off - so, if one of the batteries is not up to par, it only acts that way upon heavy load.
I'll probably take out the suspect battery and send it back to the distributor - he mentioned that I have a 1 year warranty on them. Anyway, I'm still vvery happy with the performance. I'm approaching 5,000 miles on the pack. Hopefully I can get another 95,000!
