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...
I appreciate all the advice. I charged the battery overnight by plugging the rig into a 30 amp. I took the battery out and it's in my shop now holding 13 volts. If this were my car, I'd check for voltage drop by hitting the starter. So, I attached a small 12-volt compressor and checked for drop, and it only dropped to 12.8 volts. But maybe the compressor isn't enough of a draw to matter.