It all started when my Kill A Watt stopped working. This is the device that measures my power consumption when I am charging. I also use it to verify that all of my chargers are working by the amount of power being consumed when I first plug it in. Generally, this is 1020-1070W after a commute. So I have been going without it for the last week. I have a good idea of when it is charged anyway, so I figured it wouldn't hurt to go without it until a replacement arrives.
Last night on my way home from work at midnight I started going up the one kilometer long hill when I noticed that the system voltage was lower than normal - 65V instead of the normal 68V at full throttle. So I reached over, grabbed my battery monitors and plugged them it. I gasped at what I saw: five pairs of batteries at a normal 11.5V and one pair at 5.5V! For those who don't know, anything under 10.5V for any amount of time is battery murder territory.
I feather footed it the rest of the way home, keeping the weak pair above 6V. At home I tinkered around for a bit and soon realized that one of my chargers was not charging. It turned out to be a fuse, which I replaced and it worked again.
The scary part was that I had been noticing the car was a little bit weaker the last few days, but I just attributed it to the colder weather. I really have no idea how long the one charger wasn't working and I had a bad feeling that I had murdered one pair of batteries.
I charged the pack over night and today during the day and the heavily discharged pair took 14-1/2 hours to charge. Normal is three hours if I fully charge after a drive home from work. I then split this pair and let them sit all day so I could check resting voltage to detect any internal shorts or weird self-discharging. They both rest at 13.84-13.88V, so it appears that they may live after all.
I will definitely be more careful to make sure all chargers are turning on from now on, at least until the new Kill A Watt arrives.
Wednesday, April 10, 2013
Nothing to report. Everything is working good. Drive to work...plug it in. Drive home...plug it in.
I have been meaning to double check all the battery connections to make sure they are tight - maybe this week yet. I would hate to have a bad connection a scorch a terminal.
My accessory battery charger works great.
My traction pack chargers work great.
My dual controllers work great.
My undersized, poor little SEPEX motor hasn't gone up in smoke yet.
1589 km (987 miles) on electricity so far....
What else can I say?
Posted by James Voth at 10:12 AM