Truck Camper Has No Battery Power But Works on Shore Power

Updated 02/25/2026 | Published 02/21/2026

Question:

I have a 2021 Palamino SS550 truck camper. Last Fall I winterized the unit and removed the 750 AH/ 12v Deep Cycle Lead Acid battery and put it on a charger for the winter. Last week I went to prepare the camper for use. I decided to upgrade the battery to two 100AH/12v LiFePO4 batteries wired in parallel saves weight, more than doubles battery life. When I turned on the lights to check the system, NOTHING. My camper has external battery lugs to charge the battery. Checking them I found that with the battery cut off switch off I had zero volts as expected with the switch on I had .20v. Any idea whats going on? Is my battery cut off switch the problem? I tried removing the Lithium batteries and installing the lead acid but no joy. On shore power everything works so the controller seems undamaged. Thanks for your attention.

asked by: Jim C

Expert Reply:

Hello Jim, thanks for reaching out. Since everything works on shore power, your converter and interior 12V system are fine. The problem is between the battery and the camper. Because it’s happening with both the lithium and the old lead acid, this is almost certainly not a battery issue.

The most likely causes are a blown inline fuse, a tripped/resettable breaker near the battery, a bad battery disconnect switch, or a loose/bad ground. That .20 volts reading with the switch on is a big clue that power isn’t making it past something. I’d start by checking voltage right at the battery posts, then check both sides of the disconnect switch, and look for a fuse or small breaker near the battery. One of those is almost definitely your culprit.

Check that and let me know what you find out. I'm happy to help troubleshoot further if needed.

expert reply by: Jesse M