| Re: Part # for 100amp Alternator [message #370696 is a reply to message #370695] |
Thu, 13 October 2022 08:19   |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma:
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Were I in your place, I would not work too hard for a 100amp alternator. It might not get you a lot. If you can do it with little cost/effort, it might be worth it.
For the later 26' with the house bank in the rear, the line loss at high current will do a job on trying to recover the house bank underway. You have to understand that the life of your "12 VOLT" battery is really between 11.9 and 12.6 volts. You really can't use more than about 14.4 at the battery no matter what. To get that 14.4 all the way to the back from all the way in the front, you will have to start out with a whole lot more than the roughly 15.0 that the alternators are supposed to deliver. A run-away 27SI will make 18Volts and it only takes about 16.2 to burn out every incandescent light bulb you own. (Unregulated LEDs left long before that.)
Even if you were upsize the main run to the rear that was installed as #0SAE wire (90% of the AWG), the other side is through the frame and such and you will still take about 0.5VDC beating getting to the bank (there goes your big charge).
I discovered all this when I was trying to find out why I could not recover the house bank from the converter even with my new Progressive Dynamics 9145 with Wizard. Nothing I tried could get the rate of charge over about 30amps at the best. This was frustrating because in the process of trying to diagnose my alternator belt problems, I measured (really measure like with a Bell Current probe and a Fluke 87) a charge current of 98+..... (If you did not know, the power limit of a V-belt our size is about 100 amps at 15V - that is about 2hp.)
When working about the converter problem, I actually tried a #0 welding cable from the converter to the bank only to find that I still did not get to the charge rate I wanted because the voltage loss on the negative side rose up to bite my ass.....
As you may have surmised, this was a very frustrating time because we regularly (pre-plague) would dry camp for 4 days at the Dulcimer Festival in Evart. With electric refrigeration in July, a full house bank was good for about 36 hours. When I would fire the Onan for 4 hours and only get the bank to half (by density), I set out to discover why this was. It was the distance and the lack of copper as noted above. So, I added a Pd9260 and the passengers right ankle. Now 4 hours gets us to 90%.
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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