I tow a 22-foot travel trailer and we do most of our camping in provincial parks here in Ontario. Most of the time we are hooked up to electricity full time. Does it hurt the RV batteries if you are always hooked up to electricity and the batteries are always being charged? What about during those times we store the trailer? It almost seems after I have the batteries for about a year they don't last as long as when I first got them. Every once in a while we go to parks which don't have electrical hook-ups. I do carry two batteries.
Reinhardt, (Windsor, ONT)
Reinhardt, I’m not a fan of leaving the RV plugged in non-stop unless you are close by to monitor the batteries. Overcharging is a common malady caused primarily by mediocre charging converters. There are exceptions of course; those sophisticated chargers which employ a three or four-step charging process, for example. Boiled batteries are far too common when RVs are left plugged in during non-use, unless you take the time to check the electrolyte level quite often.
It’s actually better to fully charge and then remove the batteries from the RV during any long period of non-use, especially over a harsh winter where temperatures may dip below freezing. Constant overcharging causes batteries to sulfate at a quicker rate, thereby reducing effective performance. This sounds like what you are experiencing. Decent deep cycle batteries should certainly last longer than one year.
I recommend the Xantrex Truecharge line of RV battery chargers. Most battery makers heartily favor the application of a definitive, three-stage charging process to fully and quickly charge battery systems on modern RVs. Outfitted with a sophisticated microprocessor, the charging amperages and charge voltages produced by the Truecharge2 unit, for example, are accurately regulated to provide the correct charging cycle without the risk of overcharging. This means RVs can be stored over long periods while plugged into shore power without worry. Additionally, the Truecharge2 is applicable to wet cell, gel and AGM batteries.