Thought I would post this and use it as a learning experience.
I was running my new MMM set-up in my ERBE yesterday with the "auto-Lipo" cut-off setting. Batteries are 2x (2s1P, 5.0A) Hardcase packs.
I didnt notice any performance issues during the entire run time of about 20-30 minutes of just casual bashing.
I disconnected the batteries and left them in the battery trays for a few hours till I could put the truck away and clean it up.
When I later removed the two batteries one was cool/normal and the other was warm to the touch...reading about 100deg F with digi temp.
I put my cell spy on it and it read one cell at 3.04 and the other at 3.84!
Well I had to go in for dinner, so I put my astro blinky cell balancer on it thinking to drain down the higher cell before I charge it. When I came back the blinky lights were off and I couldnt get a read from my cell spy.
I hooked it up to my balance charger and it wouldnt charge and gave a "Low Voltage" warning.
So......I changed it to NIMH charge mode at 0.5A with the astro blinky on it to try to revive it with a "trickle charge".
After about an hour, the cell spy showed the lowest cell at just above 3.1v, so I switched settings back to Lipo Balance Charge thinking I had just saved the battery from certain doom.
Since it was late, I stopped the charge cycle after another 30 mins or so with the lowest cell reading 3.34 and went to bed.
This morning, the battery wouldnt charge and I couldn't get a reading from the cell spy again.
I took it to work, restarted the process and got the lowest cell back up to 2.85 before the 120min "safety feature" of my charger kicked in. By the time I returned to check on it (15 mins later) it was completly dead again!
So here is what I am trying to figure out:
1. Did my MMM combo draw too much current and kill one of the cells?
2. Was it just the nature of lipo batteries, where sometimes a cell fails?
3. How many licks does it take to get to the center of a tootsie roll pop?
....The world may never know.