One item all RV's have in common is their 12 volt systems and batteries. Although commonly used throughout the RV industry, they are also some of the most overlooked.
We find over and over again that batteries are seldom checked and rarely serviced. Many 12-volt DC electrical problems can be traced back to the batteries. These problems range from frequently blown fuses to erratic system operations to failed converters, the latter of which is very expensive for something so easily avoided.
Checking the batteries is easy enough, but please be careful. Batteries contain hydrochloric acid in one form or another. It is very corrosive to human skin and eyes, so use a pair of latex gloves to protect your hands and cover your eyes with safety glasses. Remove the caps or covers on the top of the battery and look into each cell to check the water level. If you can see the plates, that cell needs water added to the proper level. An embossed ring inside the throat of that cell indicates the proper level. Make sure all cells are filled to approximately the same level using good city water or distilled water. Take note that not all batteries can have water added such as sealed gel batteries, AGM and maintenance free are some that cannot and should not have water added.
After water levels have been maintained, the connections and case of the battery should be inspected and cleaned if necessary. White fuzz or green crystalline growth on the positive and negative terminals indicates electrolysis and must be remedied immediately. Left unattended, this corrosion will continue until the terminals and connectors are completely dissolved, thus shutting down all 12-volt DC functions. In the interim, a hard starting generator, lights that flicker and fluctuate in luminescence, radio noise, lines on TV pictures, inverter overload, blown fuses and just a trailer full of other symptoms can and do occur, just by a "little corrosion".
This corrosion can be removed a couple different ways. The easiest to start with is spray on type cleaners. These will neutralize any surface acid and eat away a majority of the white fuzz. We have found that allowing the foam cleaner to stay on the battery for at least five minutes before washing will yield the best results.
The next method is using the good old-fashioned wire brush and pocketknife. Please use a fan to blow the dust away from you as you brush, or wet the battery with water first. Disconnect your RV from all 120-volt AC power sources such as shoreline, generator and inverter.
Next make sure all 12 volt DC systems are turned off such as refrigerator, furnace, lights and LP detector. Now remove the wire or group of wires from one post of one battery. Clean connectors and post, pat dry if wet, and reconnect. Now move to the next battery post and repeat the process. Doing it this way will lessen the confusion of trying to remember where all the cables and wires go. After all terminals and connectors are cleaned and dried, add a spray on corrosion inhibitor to prevent future problems. Check your batteries at least once a month, especially if you are always plugged in or have one or more inverters.
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