Battery voltage drops!!!

bc canuck wrote:
I have a 2015 Jayco Pinnacle with a residential fridge. When I am plugged in to shore power and have fully charged batteries (two of the biggest Trojan 6 volts that I could fit in the battery cases) my voltage readout is 13.2/ 13.3. After driving for 4 to 5 hours my readout has dropped to around 12.3 to 12.4 volts. I thought that it should at least maintain my full charge running off my truck charging system. When we then dry camp overnight my LOW voltage alarm starts to beep usually around 5 am and of course wakes me up. I did not spend 100K to have a very fancy alarm clock. Any suggestions would be appreciated. Thanks .

I would check the 12V current being drawn. It sounds like you are drawing more current than the truck can put supply. With a long 12V wire from the front of the truck back to the RV, you will be lucky to supply 8 amps. You could be drawing more than that if running the refrig on 12V.

Sometimes the 12V wire isn't even connected in the truck or RV, even though the pin is in the connector. Might check that.

The only other thing I can think of is installing a much heavier gauge 12V wire in both the truck and RV. Even if it's a 12 gauge, it may not supply enough current for your situation.