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Battery School

General Battery Care Procedures

General deep cycle battery care procedures

Reasons Why Batteries Fail

General Difference Between Gel and Wet Batteries

State of Charge and Sulfation

Connect Your Batteries for Optimum Efficiency

Just A Little Corrosion Causes Big Voltage Drops

Don't Be Misled By Battery Ratings

Which Deep Cycle Battery Do I Choose?

Daily Amphere-Hour Consumption For Your RV

Those RV-ers who prefer to stay in campgrounds with full hookups have different requirements than those who enjoy primitive camping without hookups. 

If you never boondock and always stay in places with electrical hookups, you probably can get by with one good quality deep-cycle battery.  However, those RV-ers who sometimes or regularly depend on battery power for the house systems need to do some calculating in order to have enough batteries of the proper size to meet their requirements.

The first step is to figure a typical day’s ampere-hour consumption.  It is easy to do:  Simply multiply the amperage draw of each item of equipment in the RV by the number of hours it will be used each day.  Amperage draw is found on equipment labels, stamped into the casings, or in the instruction booklets.  If your RV manual list only lists watts, watts can be converted to amperage by dividing by voltage (12 volts).  Amperage draws can be directly measured also with an appropriate “amp meter”. Typical amperage draws of common RV equipment are listed in the table* below:

Three lights for 4 hours(4 hrs. x 4.5 amps) = 18.00 Ah
Water pump for 45 minutes; includes two showers (.75 hrs. x 5 amps) = 3.75 Ah
TV, color for 2 hours(2 hrs. x 4 amps) = 8.00 Ah
Miscellaneous (clock, LED pilot lights, etc) 2.00 Ah
Total 31.75 Ah

The total daily consumption of 31.75 may not seem like much, but, in relation to battery capacity, it can be considerable.  If the RV has only one Group 24 battery with a rating of 90 Ah, using 31.75 Ah would deplete 32% of the battery’s capacity.  Two Group 24’s connected in parallel have the capacity of 180 Ah (90 Ah + 90 Ah).  A daily consumption of 31.75 Ah would deplete 17% of the capacity available.  If you dry camped for 3 day (31.75 x 3 days= 95.25 Ah), 52% of your battery capacity would be depleted.  The more Ah capacity that is available to your DC accessories, the longer your systems will run.  You can increase more Ah by using either higher capacity batteries or connecting multiple batteries (2 or 3 or 4) in parallel, if you have room in the battery tray.

* This information is taken from “RV ELECTRICAL SYSTEMS-A Basic Guide to Troubleshooting, Repair and Improvement” by Bill and Jan Moeller, 1994, Ragged Mountain Press, Camden, Maine.

Safety Tips on Charging Batteries

Determining When A Battery is Fully Charged

Why Are My Batteries Discharged

What is the difference between series battery connections and parallel battery connections and how do they increase battery capacity and voltage?

Jump start procedures

Preparing your batteries for winter

Advantages and Disadvantages of using two 12 volt batteries connected in parallel or two 6 volt batteries connected in series.

Testing the battery