Our battery in the RV went down this weekend and wouldn't stay up while running down the road. I checked it once back home, and with the switch in "Store", the battery puts out about 8.5 volts whet...
Sounds like the battery is dead, at 8.5 volts! The 12.5 volt reading is from the alternator. The battery should have some sort of warrenty, you probably wont get full refund but should get something!