Electrical Issue with Battery Disconnect

[BillyMcIntyre]

We have a 2019 Flagstaff T21DMHW AFrame that we bought last fall. We are taking it out for the first time next weekend. When I bought it last fall, the folks we bought from said the battery disconnect switch had gone bad. I ordered a new one and wired up exactly the way the other one was wired. With the switch turned to on and connected to shore power, you can hear the battery trickle and charging. I have pulled all of the cables, charged the batteries to double check, and everything is good. The problem is as soon as I unhook from shore power, I am getting nothing from the batteries. It won't even power the tongue jack but a few seconds and the batteries seem dead. I even went in and turned the roof fan on and it will run but when trying to turn a light on inside it wouldn't come on with the fan running. I obviously am getting nothing from the batteries off shore power. What am I missing? Is there another switch somewhere to go from shore power to battery power? I am stumped! If need be I could take pics but everything seems right.

[mmartin_tdc]

I would suggest the place to start is charge the battery overnight, then unplug the charger and let the battery rest - no load, then take a meter reading, if below 12v - battery is toast.
If battery tests good, ---- maybe try bypassing the battery cutoff switch. Possibly something in the way it was wired is wrong and you just copied the "wrong" when you replaced the swith.

[pgandw]

The battery disconnect is NOT a factory-installed item. The switch was installed by either the previous owner or the dealer who sold it to the 1st owner. It sounds like the previous owner was having battery problems, and decided it was the disconnect switch that was the problem (which may or may not be true).

I'm suspecting your battery is toast, and won't hold any reasonable amount of charge. If the battery(s - your post isn't clear as to 1 or 2 batteries) are the original delivery, they are toast after 5-6 years. I suspect the disconnect switch was installed because the batteries were being totally discharged between trips, which would have shortened their life.

I also have a 2019 Flagstaff T21TBHW. I installed dual Costco GC-2 batteries with a disconnect when I took delivery in Sept 2018. These are now nearing end of life - they maybe have 50% of their original capacity left.

Voltage readings under load - see how low the voltage sags when under load - or load testing at a car parts place will tell the story. One of the things that shortened my batteries' life was me not catching that the fuse in the charge line to trailer on the tow vehicle had blown, and the batteries were not getting any charge while driving. Several days on the road dry camping at night was enough to seriously run them down.

Fred W
2019 Flagstaff T21TBHW A-frame
2022 Hyundai Palisade