Whether you’ve been parked for the winter or winterized for the season, odds are that you haven’t thought too much about your batteries.
But now that spring has arrived a lot of us are getting ready to hit the road and want to make sure that when we want & need power that it is there and is reliable. While you may be plugged into shore power most of time, while you’re underway and at remote spots you will be on your own.
Whether or not you have an inverter, generator, solar panel, etc.; there is always a need to maintain good 12 VDC power for your various RV systems. In fact, some of your systems may not operate (or may not operate correctly) at all under low DC power conditions. This includes your refrigerator and for some rigs their hydronic heating/hot water systems, remote electrical lights, electric flush toilets, etc.
So this is the perfect time to make sure that your batteries are up to the task at hand.
Always wear safety glasses, protective gloves and other protective gear when working around batteries!!!
If you have flooded batteries with removable caps, make sure that you have adequate levels in each cell. If low, you will need to add distilled water. Please be sure to observe all safety precautions and use a battery fill syringe/container. Never overfill!!!
Next I like to make sure that if any battery fluid — which is a strong acid — has escaped due to boiling over, venting, cracks, etc.; that it is neutralized. For this I use baking soda mixed in water and applied lightly to all surfaces of the battery avoiding the terminal posts and vent caps/covers. I use a folder over paper towel dipped in the baking soda solution for this step. Please be sure to observe all safety precautions. I am not attempting to neutralize the acid, merely detecting its presence.
If there is any bubbling, meaning that the acid is reacting with the baking soda, then you will need to determine the cause and possibly will need to replace the battery. Whether or not the battery is replaced, the presence of acid means that you will need to perform a thorough neutralization of the acid, cleaning – including underneath the battery – flushing the compartment, etc.
Keep in mind that if battery acid did leak, you need to find and correct the source of the problem ASAP. Your battery may be failing, your charger may not be limiting output as the battery approaches full charge causing an overcharge, etc.
My next step is to remove each cable, clean the cable and post, reconnect and then coat with battery grease. Only perform this step if you are confident in your abilities as shorting out a battery or reconnecting one incorrectly can cause serious injuries and/or equipment damage. Please be sure to observe all safety precautions.
Finally, I like to check the battery capacity. At a minimum (with shore power removed and no loads connected) I check the voltage of each battery and then I repeat with shore power/charger attached. This lets me confirm that the battery output at rest and the charge levels are as expected. The actual values will depend not only on the condition of the battery but also how your charger works and if there are any phantom loads.
BTW, a better test is to check the specific gravity of each cell, but not everyone wants to do this or buy (not very expensive but something that I often lose each season) a hydrometer.