Discovery: Aux battery shutting off

[Jablonsa20]

Last week we were camping plugged into shore power 50 amp. For about a week. No issues everything was working normaI. I decided to change my fuel filters because they were due. Did the prime but it didn't start right away. As I was turning the engine over everything on the coach went dead, dash, aux power, After that it was slow to turn over so checked my coach battery and had a bad battery. Replaced it, But I couldn't get the aux battery disconnect to turn back on. While redoing the priming it kicked back on. After a cpl more times priming the rv started and runs great. But my problem now is anytime I try to use something that is under the aux battery ( water pump, lights, ac or heat it trips the battery disconnect and I am un able to turn it back on until I restart the coach but as soon as i try to use again it trips. My main battery side for the house stays on, the fridge is on along with some outlets and tvs. Both inverters are working showing full battery and charging. I have tested the batteries with a volt meter and all 6 - 6volt house batteries seem good. We are plugged into a 50 amp shore power as well.
What could be causing this?

[computerguy]

Hmmmm. Recently I had an intermittent problem with batteries, BCC or connections. It took months to troubleshoot because it was intermittent.
My problem was simple but double pronged. I had corroded connections to the BCC and a deteriorating interconnect solenoid.
The BCC controls a ton of stuff in your rv.
I had to wait until the problem was happening then start troubleshooting. Get out the multi meter and check voltages. I was fortunate enough to already know a lot about my BCC due to my solar and lithium install.
Cleaned all my battery electrical connections and replaced the interconnect solenoid and my problem is fixed.
I think I did a post on it in the forum a few weeks ago. BTW the connections didn’t look bad but when I took them apart is when I could see the corrosion.

[Toribk]

Both corrosive battery lugs and hidden corrosion in encapsulated battery wiring is typically the result of "off gassing" from using wet cell batteries.

For this reason, along with others, I advocate the use of AGM house batteries in both marine and RV applications.
I recently replaced my first set of AGM batteries after 10 years and as you can see in the photo, the battery compartment and all the cabling looks like the day I bought the coach.

Gradually, the RV Industry will embrace Lithium batteries as cost come down and mainstream affordable units come equipped with adequately designed control and charging systems to accommodate them.

[computerguy]

Originally Posted by Toribk

Both corrosive battery lugs and hidden corrosion in encapsulated battery wiring is typically the result of "off gassing" from using wet cell batteries.

For this reason, along with others, I advocate the use of AGM house batteries in both marine and RV applications.
I recently replaced my first set of AGM batteries after 10 years and as you can see in the photo, the battery compartment and all the cabling looks like the day I bought the coach.

Gradually, the RV Industry will embrace Lithium batteries as cost come down and mainstream affordable units come equipped with adequately designed control and charging systems to accommodate them.Attachment 393937

My corrosion was at the chassis battery compartment. For me this is in the front exposed to the weather while driving. Was the water/weather that corroded it IMO.

[Toribk]

Yep.......gassing, water, and rain water infused with road salt/brine or salty air near the East Coast are never good for batteries or electrical systems in general.

Up front on my coach,where I have a gap between the hood and lower cowling, I made a firewall skirt out of Sunbrella fabric to keep rain water off the firewall where there are a number of chassis wiring harness connections as well as main power post studs.

[JACKARMYRET]

I recently had a similar problem and it was my battery cables, so I replaced all. Had to start up coach to get control panel to light up etc. My electrical problems sounds similar to yours.