Today was an interesting drive in my EV. The weather was very snowy, but I drove the EV anyway. I've never had the chance to drive it in the snow yet. It has been on blocks during the last two winters for various work.
The ride in the morning was very uneventful. The car handled very well in the snow. When I got back in the car after work, the car was dead. No gauges, no radio, no fan, etc. At that point, I realized I had left my lights on all day. Crap! However, I was prepared for this. I have been carrying a couple of 10 ga. wires in my trunk for just this reason. Each cable had an alligator clip on one end and a ring terminal on the other end. With the key on, I connected the clips to the 12V battery terminals and simply touched the ring terminals across 4 of the LiFePO4 cells. That was close enough to 12V. With that voltage, the main contactor engaged and the DC-DC converter turned on. After that, I could remove the cables because the DC-DC converter was keeping the 12V system alive. I was pretty happy with my solution until I got back inside the car. The process of killing and jumping the battery had reset my "fuel" gauge, but I could tell from the voltage meter that I didn't have a full charge. In fact, I could tell I had gotten very little charge. Unfortunately, I no longer had range to make it back home. Luckily, my local mechanic was within range, so I drove it there to charge overnight, in a nice, warm shop and caught a ride home with a friend that happened to be picking up a car there. It took me some time to realize what must have happened. My MiniBMS system has a DC-powered Solid State Relay to disconnect the charger from the incoming AC line if a cell is being overcharged. Because of this, my car requires a solid 12V system (but not a lot of current) in order to keep charging. When I left the lights on, my car only charged as long as the 12V battery held up. Because the battery is very small (and kind of old), I don't think it lasted very long with the headlight load. So, watch your 12V systems! It is quite possible you need that system to recharge your EV! Mike www.evalbum.com/2778 _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
