Sunday, December 28, 2014

Battery and charging forward..

I have been busy with work and holiday schedules but made it out to the garage to check on the batteries.
I took some readings after charging and letting the batteries rest for a few weeks, I found that one cell had dropped to nearly zero and the other 49 were at 3.31 +/-.
I managed to work the cell out without full disassembly of the rear pack and install a spare cell that came with the original set of batteries.
I put it on charge and cut the charge off when the cells all read about 3.51. I would have fully charged, but wanted to watch the finish due to no BMS, I will come back to this when I have some time to monitor things.

Saturday, December 6, 2014

Oh Crap

Since it had been a while since I checked on all the vehicles I thought I would check charge on the car and other projects. I turned on the Mazda and... NOTHING, not a good feeling.
The batteries were all at less than 1 volt, I assumed I had destroyed the battery pack.
I put the plugged in the charger and the voltage came up to 2.5v a cell quickly.
I charged for 10 hours at about 8 amps, so far the voltages are very close and holding, I have yet to take it for a test drive and check the capacity.
I wanted to bottom balance the pack, but not like THIS! I am not holding much faith that the pack is good as the voltage is never supposed to go under 2.5v a cell.
The lesson learned, even though I had good intentions on checking the charge, I should have disconnected the pack. 
I guess I will find out if you can fully deplete a Lithium battery and bring it back to life.