Jim,
I have the same battery in 829CC. It has performed very well since April. Some time ago, I inadvertently discharged it to 3.4 volts because the back up GPS was plugged into the the auxiliary with the screen dimmed but the unit on. I now always pull the plug.
Since Andy was not around to offer advice, I took a chance in an effort to restore the battery rather than junk it. According to what I was told by Andy at the time of purchase, the battery had to be returned to him for recovery in the event of a deep discharge.
Using the balancer/charger I first set the voltage to 6 volts and selected charge. That brought the voltage up to just over 6 rather quickly. Next, I did the same with a setting of 9 volts. That worked but took longer. After that I used 12 volts which worked but took several hours. The battery has worked flawlessly since and seems to hold a voltage of 13.3 between flights. Jake