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fcooper's avatar
fcooper
Explorer
Dec 08, 2013

Charging System, Moderately High Voltage, need ideas

The motorhome is described in signature block below. With the VMSpc monitor, I normally see voltage in the range of 13.6 to 13.8. Today on the highway, I am seeing 14.1 to 14.3, then back to 13.9. When stopped for a quick lunch with the engine on fast idle (1000 rpm), I was seeing 14.3 and sometimes 14.4 volts. We were operating in temps of 40 to 50 degrees, so I don't suspect the grid heater turning on.

On this coach, the house batteries are not linked to the cranking batteries in any manner, so the alternator is only charging the cranking batteries and supplying voltage to operate the chassis.

Need advice on what the most likely cause of this could be, or maybe some troubleshooting advice. I'm thinking one or both of the 2 year old cranking batteries may be going bad, but they still crank great. I felt of both of them as soon as we stopped for the day, and they were not warm so I don't suspect overcharging. I'm also considering that the voltage regulator in the alternator may be beginning to fail. The alternator has about 100,000 miles on it.

Is 14.3 to 14.4 too high for charging voltage? Your thoughts appreciated.

Thanks

Fred

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