I just cooked one of my two wet cell batteries (Interstate deep cell). Question: Is it a good idea to keep your 30-amp trailer plugged into a 120-volt source while parked at home for 30 days straight? Would it be better to get a satellite battery maintainer? —Paul
Leaving your rig plugged in or not when the trailer is parked at home depends on the type of converter/battery charger you have. Since you indicated it was a trailer, I would assume you have a conventional charger that puts out 13.6 volts when the battery draws down and then goes to 13.2 volts to just maintain the batteries. If you “cooked” one of your batteries, I would assume the converter is bad and did not go to the maintenance phase.
However, when lead acid batteries drain down, sulfur coats the plates. If you do not have a multi-stage charger or “conditioning” model, the sulfur gets thicker and thicker and eventually will not hold a charge. So, just leaving it plugged in or even using a satellite trickle charger will not condition them.
Since I believe your charger is no good, I would suggest looking at a new charger that has the conditioning or desulfation setting. My recommendation is the Progressive Dynamics unit with Charge Wizard. Then you can leave it plugged in and the batteries should last 2-3 times longer. If you have an all-in-one unit, which has the converter inside the distribution center, and don’t want to replace the entire unit, you can just get the standalone version and disconnect your converter section of the distribution center.