I didn't drive my CB for over a month. I put the trickle charger on, and left for vacation. When I got back, the battery was pretty much dead. I looked at the fluid levels, and saw that one (only one) cell was at half level. Any ideas on what could have done this? It is a relatively new battery, bought about 3~4 months ago from Walmart. So, I topped off the battery and put it back on the charger. It won't hold a voltage beyond 12v. I am thinking the battery is gone.