By Russ and Tiña De Maris
A dead RV battery is always a frustration, and oftentimes a mystification. Why did it die? RV batteries are good for a limited number of use/charge cycles. As we’ve often commented, the “deeper” you draw a battery down, the fewer use/charge cycles you’ll get out of it. We try (emphasize “try”) not to let our batteries get down to less than half a full charge before we see to it they’re charged up. That’s a big part of the battle right there.
There are “things” that happen, and we’re all familiar with them. Like the time we found our truck camper battery flat for no good reason – until we did a little investigating and found that the clothes closet door latch wasn’t latching right, and the door was open just a skosh. That skosh was big enough to allow the closet light switch to activate, illuminating the empty hanger rod until the battery went south.
But even with everything in its place, there are mysterious causes of battery failure. We’re not talking about UFOs landing on your RV roof and taking a jump-start for their warp drive. We’re talking parasites.
Like fleas on your dog or cat, these little tiny loads can turn into long-term lifeblood suckers from your RV battery. What are they? One is the circuitry in the LP gas alarm. That little sniffer, sitting there inconspicuously at floor level, draws on your battery 24-7. What else? Some electronic entertainment equipment may draw from your 12-volt system without you being aware of it. Just keeping the memory up in your stereo radio can chew up the volts. There are all sorts of “little” electrical loads that can slowly deplete the battery in your sleeping RV.
What to do? One way of dealing with parasites is to hunt them down and disconnect them. That leads to its own set of problems. Say you disconnect your LP detector – but then forget to hook it up when you hit the road. Then you’re without the protection the detector provides.
Another way is to make sure your batteries are fully charged and then disconnect the battery from the “house” loads. How? Just remove all the wires connected to the negative battery post. When the time comes to hit the road, reconnect the leads and go. Of course, you’ll lose anything in “memory” in electronic devices; you might lose favorite radio “presets.”
You could leave the shore power cable hooked up and hope your power converter will keep the battery charged – without overcharging it. Our fifth wheel converter simply doesn’t keep our battery charged, while in other rigs the converter may “cook” it.
For us, we’ve found the best answer is to leave the rig unplugged, but put a “smart” charger onto the deep-cycle battery. Our smart charger keeps the battery full, but doesn’t allow for overcharging. It also has a pulse system that is said to break up the formation of sulfates on the battery plates – a leading cause of battery failure.