Electrical Problem

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July 10, 2012

Ken Freund- Tech Tip of the MonthBy Ken Freund
I replaced all batteries in my motorhome. I checked voltage use from negative posts to ground of the coach battery and found an 8-volt draw on my batteries. I checked all 12-volt circuits and couldn’t find a short. I don’t know what to check next. Can you help me? My motorhome is a 1991 Cruisemaster by Georgie Boy on a John Deere chassis.

Ervin Gibbs
Good Sam Member

If those batteries have been trouble-free for four years, you don’t need to do anything. You might pop the caps to see if they’re going dry. Don’t replace until they go bad. You need to be measuring amps, not volts. A draw of about 0.050 amp or so is normal. There are memory circuits in the refrigerator, computer, alarms, etc.

Remove fuses one at a time while test ammeter is in series with battery to find which circuits are drawing how much. You may need to install the battery disconnect switch or use maintenance charger.

Ken Freund
Good Sam Club

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  1. James S Cooper

    I have been rving for thirty plus years.I use a series 8D battery.Oft called a CAT battery,1300cca.I used to do a lot of hunting and this battery kept the furnace and lights on for up to five days without recharging.Temperatures occasionally hit -30C.I have so far averaged 8-10 yrs on a battery.The one disadvantage is the battery is getting heavier every year.About 150 lbs