Dead Chassis Batteries

[Mike Gamble]

At DRRX DrDave managed to change the source of power for our RV refrigerator/freezer from the chassis batteries to the coach batteries. I had thought that would eliminate the chassis batteries going dead when dry camping. But, someone mentioned the possibility that a drain may be going from the chassis batteries through the alternator. The symptom seems to be a "warm alternator". I'd be interested if anyone has ever encountered this problem....and potential solutions????

[H. Miller]

A large diode would allow current to flow in only one direction

[Old Scout]

Interesting--after years of storing our 03 coach with power, we moved to our barn which is off the grid. I immediately started noticing that the chassis bats would go dead in about a week or two--in fact I bought new bats thinking they were the problem--they werent. Turning off the main chassis bat switch seemed to help but it appears there is still a phantom draw somewhere in the coach. Had to replace the alternator on this trip so it will be interesting to see, if when we get back home, the "status quo" at the barn has changed.

[Basil Shannon]

Quote:

Originally Posted by Mike Gamble At DRRX DrDave managed to change the source of power for our RV refrigerator/freezer from the chassis batteries to the coach batteries. I had thought that would eliminate the chassis batteries going dead when dry camping. But, someone mentioned the possibility that a drain may be going from the chassis batteries through the alternator. The symptom seems to be a "warm alternator". I'd be interested if anyone has ever encountered this problem....and potential solutions????

Several years ago when Bob Kapp & I had a cronic dead chassis battery problems while dry camping, WRV sent Mark to Las Vegas and he installed a relay in the alternator excitation voltage circuit activated only when the key was in the on position. Didn't really help. After a year or more of fighting the problem, it ended up being bad chassis batteries. You might have the chassis batteries load tested.

Rained all night in Palm Springs!

[Old Rv'er]

Hmmm, I would check the "Load Sense" wire from the back of the alternator to the batteries. I don't know as there is a diode in line with this wire, but if my memory serves this is a direct connection. On the LN alternators, there is a ground wire which is not needed if you change to a Delco model. I have not experienced this issue more than once when we did have dead starting batteries after leaving the coach unplugged for a month. Engaging the boost switch got me started, and since then no issues.

Rained from about midnight to dawn in Las Vegas, NV.