| Unusual electrical issue [message #339144] |
Thu, 29 November 2018 00:06  |
Hal StClair
Messages: 971
Registered: March 2013
Location: Rio Rancho NM
Karma:
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Senior Member |
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I just ran into an interesting issue on our Thanksgiving trip. After replacing a NEW alternator under warranty after little over 1000 miles, I was afraid the replacement was going bad 5000 miles later. The voltage would drop to 11.9 volts and randomly jump to 14+ at times. While observing -12 volts a semi truck passed and the voltage popped up to 14+ and seemed to drop as soon as the big rig passed. I noticed the same effect when going under an overpass. It then hit me-the solar panels (280 watts worth) are wired to the house battery bank and the alternator sense wire is attached to the same point on the isolator. It seems the voltage from the panels is making the alternator reduce output thinking the battery voltage is satisfied. Guess I'll have to install a relay to open the PV circuit when the ignition is energized. Who'd of thunk that would happen? It's always something to keep the gray matter going on these GMC's.
Hal
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."
1977 Royale 101348,
1977 Royale 101586, Diesel powered,
1974 Eagle Bus 45',w/slideout,
Rio Rancho, NM
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