Battery Hold-down Strap Shorting Against Positive Battery Post
I have had my 2011 twin interstate motorhome for about ten months. I purchased it new from the closest dealer (450 miles away). Last fall, I lived in it for five months while wintering in Texas. I was usually plugged in and was only unplugged for24-48 hours at the most. So I never exercised the coach batteries. Now that is summer and I store the interstate in a building out in the sticks that does not have electricity. With the Coach DC switch turned off, the batteries only last for two or three days and then are dead.
It also seemed like the batteries would never fully charge. The best I could get was 13.66 volts. I decided to remove the batteries and have them tested at a local golf cart dealer shop. When I took the top off the battery box, I found that the metal hold down bar was shorting against the positive terminal on one of the batteries. The hold-down wing-nut was not tight and the batteries would easily shift around. The metal hold down bar was shrink-wrapped, but it had worn through and was shorting out. I noticed sparks when I went to move one of the batteries. I have posted the pictures that illustrate what you might want to look for…
For the fix, I inserted two five inch pieces of 2X4 alongside and between the batteries to keep them from shifting. I also repositioned and tightened down the hold-down strap. I will check it again after my next trip to see if there was any movement.
Airstream might want to consider making this hold-down bar out of a plastic material that is non-conductive.