Tips to Extend RV Battery Life
Posted by Shawn Friesen | Vice President of RVT.com on May 25, 2009Misconceptions about battery charging can drain the life from your 12-volt RV batteries prematurely, forcing you to replace them more often than should be necessary. Overcharging and undercharging are the two most common reasons RV batteries fail before they should.
Overcharging occurs when you leave your RV plugged into the built-in battery charger during storage. “The problem is many converter chargers provide a constant charge of about 13.5 volts, which is too high for fully charged batteries,” says Mark Polk on the Family Motor Coach Association website. Instead of keeping the battery “topped off,” Polk warns this practice actually “boils off” electrolytes, resulting in severe water loss, plate corrosion, and “an early death for the batteries.”
Undercharging occurs when you repeatedly fail to fully recharge your batteries after each discharge. “If a battery is not recharged, the sulfate material that attaches to the discharged portions of the plates begins to harden into crystals,” called sulfation, Polk explains. “Over time, this sulfate cannot be converted back into active plate material and the battery is ruined.”
The following tips from Polk can help prevent over- or undercharging and double the life of your RV batteries and keep your recreational vehicle on the road longer:
> Recharge batteries at 80% (12.4 volts) to prevent sulfation.
> Don’t allow batteries to discharge below 10.5 volts.
> Batteries discharged to 50% instead of 80% will last twice as long.
> Turn off the battery disconnect when your RV is in storage or not in use to prevent electronics from discharging the batteries.
> During periods of hot weather or high use, check batteries frequently and add distilled water as necessary.
> Batteries can self-discharge by as much as 10% a month, so check batteries periodically when your RV is in storage.
November 10th, 2009 at 2:07 pm
Ah!!! at last I found what I was looking for. Somtimes it takes so much effort to find even tiny useful piece of information.
Nice post. Thanks
November 10th, 2009 at 2:45 pm
Glad we could help. Come see us again ; )
June 8th, 2011 at 12:12 pm
I understand that if the RV is plugged into shore power, disconnect the ‘house’ batteries so not to overcharge. I read somewhere that after (2-4) days, disconnect, and reconnect prior to leaving the campground. Is that correct?
Thanks,
Joe Collins
June 9th, 2011 at 12:37 pm
Good question, I asked an RV Parts and Service manager that I know, and here’s what he said, hope it helps:
“If you are not using the motor home it is fine to have the house (RV) batteries disconnected, so they do not continually charge when plugged into shore power. The batteries should not overcharge if left connected, but you will need to top up the water level in the batteries more often, as they are being charged whenever the unit is plugged in to shore power. Heat and gas evaporation during battery use and charging causes water to deplete from the battery, make sure that distilled water is the only thing you add to top up the fluid levels, and don’t overfill the batteries, as the fluid may leak out during charging. If you are using the unit you may have to keep the battery switch on in order to use any of the 12v lights or propane appliances, so you won’t be able to disconnect the house batteries.”