| Re: [GMCnet] [GMCMH-EFI] speaking of alternators... [message #322173 is a reply to message #322171] |
Tue, 15 August 2017 19:41   |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma:
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Senior Member |
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Ken,
As usual, what you wrote is accurate - for the larger part.
But,
There is the case of the GMC 23s with the house bank in the front. Then, someone upsized the cables from the isolator and to ground as #4 AWG. So, when departing from a weekend of dry camping (with the OE reefer) the alternator belt will squeal and get a surface glaze that makes it even worse than it was.
And I am thinking, "It is an old design 80 amp alternator, what is going on??"
I got a new belt and reset the experiment at home. This time with a Bell current probe attached to a Fluke....
Fire up!!
What The ??
Squeal !! 96 Amps out of the machine and all of 80 to the House Bank.?
!Shut it Down.! Lets not do that again. That started the dual belt plan.
We go back on shore power and guess what??
Nothing, that's what. And that is with a PD 9145.
The best it would do was 27 amps into a 60% house bank. (So much for the 45 rating.)
Shortly after I got the coach (and fried the first of 2 4Ds), I replaced the buzz box with a PD9145w/wizard.
It turned out that the culprit here was the #10SAE (~9.4AWG) from the back to the front that not only supplies all the house electric to the fuse panel in the back but is expected to do the reverse to recover the house bank from the buzzbox. At only 27 amps, the voltage drop between the PD9145 and the bank was 0.8V. So available charge E was only 13.6.
This story could go on a lot longer and there are actually many parts of this that have been condensed. I would love to have you think I got all of this figured out this fast.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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