Coach battery going dead.

RobCosme · August 12

I recently replaced my power converter because the old one was only charging to 9 volts... Now my house batteries are charging fine.. but my chassis battery, which was only 2 months old.. will no longer hold a charge. I had to return it today for a replacement.

I can not find anything inside the coach that would be drawing on the battery.. but it is obvious that something is killing my chassis battery.

From a few Youtube videos.. it is suggested that maybe I have a bad Battery Relay Isolator. and I have identified possibly replacing it with a Stinger Battery Isolator. So it comes down to finding the isolator inside my coach. I am attaching a photo of a panel located on the right side of my engine compartment and facing forward. I am not sure if this is the isolator. It looks similar to the Stinger, but not exactly.

My coach is a 2004 Damon Daybreak and I didn't get much documentation with it when I bought it.

Any help would be greatly appreciated.

Rob

Edited August 12 by RobCosme
I mention coach battery instead of Chassis battery

Kirk W · August 12

Do you have a multimeter to use in troubleshooting? When you say that the battery will no longer hold a charge, do you mean that it does not charge up when the engine is running? In many cases the converter does not charge the chassis battery and I don't know which way Daymon is set up. From what you say I'm thinking that the battery does charge properly while you are driving, but will self discharge when sitting parked?

What we tend to call a battery isolator is a solenoid that allows you to disconnect the battery when it is in storage to keep it open circuit and charged. That device is a latching relay to stay open or closed with out any power consumption. That appears to be the top device in your picture.

There is also a Charge Solenoid that is installed to connect both the chassis and battery banks together. This solenoid is engaged whenever the ignition key switch is in the “on” position. The engine can then recharge both battery banks when driving down the road. I believe that to be the bottom one in your picture.

There could also be an Emergency Start solenoid that can be triggered to connect the coach and chassis batteries in parallel if needed to start the engine.

RobCosme · August 12

Thank you Kirk...

The chassis battery charges fine while the engine is running... but it has been parked for about a month since our last trip and the chassis battery was totally dead. I placed the battery on an external charging station but it won't charge the battery.. I get an error message that says Check Battery. and a reading of .01 volts. I'm assuming the battery went bad.

I do have a 30 amp shore power head installed at my house and it was plugged into shore power during that month that the battery died.

Kirk W · August 13

It is probably quite normal that your shore power to the converter does not charge the chassis battery as most are that way. But, while it is not uncommon for the chassis battery to be discharged while in storage, that is way too quickly to be considered normal. The symptom that you have is what we call a parasitic load, or something that is not being turned off when the RV is not running. You have not mentioned what your RV is , make & model or the age of it, nor the reason that you replaced your converter? While it is possible that there is some connection between the replacement and the new problems, it could be unrelated as it is a fairly common problem. There are several things about motorhomes that are normally power from the chassis battery rather than the coach batteries, such as an electric entry step. Another thing you have not said is whether or not you have a battery isolator for the chassis batter that you use when the RV is in storage. Also, how long have you owned this RV and are you the first owner.

One way to be sure that the chassis battery has nothing taking power from it while in storage is to lift the negative cable from the battery post when you park it.