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Re: Flat battery today ...alternator? [message #370476 is a reply to message #370475] |
Sun, 11 September 2022 08:35 |
boybach
Messages: 566 Registered: December 2020 Location: Vancouver Island
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Matt - I have an appointment this (Sunday) morning at my alternator re-builder's place: the owner is making a special trip into town to open up his place for me. I'm bringing the battery and alternator into him for testing. Before I got any advice here I assumed the alternator had developed a problem so I removed it.
I hadn't had any charging issues like this before and because the positive lead to the battery from the solenoid didn't show more than 10 or 11v with the engine running I made that analysis. Now I see the isolator is where I should have placed my meter. Oh well, I can do that when I get back out to the coach and reassemble everything (if the alternator tests good)
Thinking about the role of the isolator and the fact that my battery was down so much after behaving normally just last week, am I right thinking a failed isolator could have allowed my house batteries to draw down the chassis battery?
Larry
Matt Colie wrote on Sun, 11 September 2022 05:19Larry,
Yes, your charging system has failed, but don't go buying parts before finishing the diagnosis.
You have a meter? If no, go get one.
Measure the battery voltage.
Fire the engine. Measure again.
Measure between the center of the isolator and the plate. Should be 14+ with the engine running. Less than that check alternator connections.
Engine Off. Headlights on.
Measure between the battery + and the terminal on the boost contactor. Same as the battery?
Same for the battery - and the aluminum ground plate where things are mounted. Same? Ok connections are good.
Engine off.
If you were good to there, pop the wires off the islator and set the meter to resistance. May be marked as Ω.
Check between the center and both others one way and then reverse the test leads and do it again. If you don't get a difference one way and not the other, things are good.
Isolator failures are rare, but do happen.
Good luck Be sure to tell us what you find.
Matt
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
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Flat battery today ...alternator?
By: boybach on Sat, 10 September 2022 19:56
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Re: Flat battery today ...alternator?
By: JohnL455 on Sat, 10 September 2022 21:10
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Re: Flat battery today ...alternator?
By: boybach on Sat, 10 September 2022 23:32
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Re: Flat battery today ...alternator?
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Re: Flat battery today ...alternator?
By: boybach on Sun, 11 September 2022 08:35
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Re: Flat battery today ...alternator?
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Re: Flat battery today ...alternator?
By: boybach on Sun, 11 September 2022 10:41
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Re: Flat battery today ...alternator?
By: boybach on Sun, 11 September 2022 21:48
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Re: Flat battery today ...alternator?
By: JohnL455 on Sun, 11 September 2022 10:37
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Re: Flat battery today ...alternator?
By: boybach on Sun, 11 September 2022 20:43
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Re: Flat battery today ...alternator?
By: RF_Burns on Mon, 12 September 2022 07:49
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Re: Flat battery today ...alternator?
By: boybach on Mon, 12 September 2022 10:05
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Re: Flat battery today ...alternator?
By: JohnL455 on Mon, 12 September 2022 11:00
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Re: Flat battery today ...alternator?
By: boybach on Mon, 12 September 2022 11:46
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Re: Flat battery today ...alternator?
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Re: Flat battery today ...alternator?
By: RF_Burns on Mon, 12 September 2022 11:54
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Re: Flat battery today ...alternator?
By: boybach on Mon, 12 September 2022 17:44
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Re: Flat battery today ...alternator?
By: RF_Burns on Mon, 12 September 2022 22:37
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Re: Flat battery today ...alternator?
By: boybach on Mon, 12 September 2022 22:57
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Re: Flat battery today ...alternator?
By: boybach on Mon, 12 September 2022 23:10
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Re: Flat battery today ...alternator?
By: RF_Burns on Tue, 13 September 2022 07:34
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