So What charges What in battery land [message #365581] |
Tue, 20 July 2021 22:44 |
boybach
Messages: 566 Registered: December 2020 Location: Vancouver Island
Karma: 4
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Ok, I was under the impression that Onan charged house and chassis batteries but I now see that it only charges house bank.
Does the alternator charge just the chassis battery or does it charge both?
Larry
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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Re: So What charges What in battery land [message #365582 is a reply to message #365581] |
Tue, 20 July 2021 23:14 |
Ken Burton
Messages: 10030 Registered: January 2004 Location: Hebron, Indiana
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The alternator charges BOTH battery systems (engine and house) through the isolator.
The Onan (or shore power) charges the house batteries through the 120vac to 12vdc converter.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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Re: So What charges What in battery land [message #365584 is a reply to message #365582] |
Tue, 20 July 2021 23:37 |
boybach
Messages: 566 Registered: December 2020 Location: Vancouver Island
Karma: 4
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Ken Burton wrote on Tue, 20 July 2021 21:14The alternator charges BOTH battery systems (engine and house) through the isolator.
The Onan (or shore power) charges the house batteries through the 120vac to 12vdc converter.
Thanks Ken, that's clear now.
cheers
Larry
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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Re: So What charges What in battery land [message #365587 is a reply to message #365584] |
Wed, 21 July 2021 03:54 |
Ken Burton
Messages: 10030 Registered: January 2004 Location: Hebron, Indiana
Karma: 10
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boybach wrote on Tue, 20 July 2021 23:37Ken Burton wrote on Tue, 20 July 2021 21:14The alternator charges BOTH battery systems (engine and house) through the isolator.
The Onan (or shore power) charges the house batteries through the 120vac to 12vdc converter.
Thanks Ken, that's clear now.
cheers
Larry
There are other non-OEM configurations / options available that are in my opinion of dubious benefit. The description that I gave you is the way that GM built it and do not reflect PO later changes.
I would look at replacing the converter with a stepped voltage one so you can leave shore power plugged in long term without over charging and destroying batteries. They are getting very expensive these days. I like the Progressive Dynamics ones, but there are other brands out these that I have no experience with.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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Re: So What charges What in battery land [message #365589 is a reply to message #365581] |
Wed, 21 July 2021 07:17 |
JohnL455
Messages: 4447 Registered: October 2006 Location: Woodstock, IL
Karma: 12
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For $70 you can have the 125VAC to 12VDC converter charge both battery banks by adding a Yandina combiner across the isolator battery terminals and ground. Simple elegant solution without a bunch of reengineering and cost.
John Lebetski
Woodstock, IL
77 Eleganza II
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Re: So What charges What in battery land [message #365590 is a reply to message #365581] |
Wed, 21 July 2021 07:17 |
Tilerpep
Messages: 404 Registered: June 2013 Location: Raleigh, NC
Karma: 7
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40 years of who knows what makes me want to add “verify your set up”.
Once you know what a combiner, isolater and charger in several forms are, you can probably reverse engineer your current setup. Factory used an isolater, it is what allowed alternator to charge house and engine batteries. Onan did not charge engine battery in this setup.
Combiners were popular to add because they offer charge to occur to both systems from either direction and can be installed with or without leaving the isolator in place. It is worth figuring what you have on this question because it changes what happens in failure mode
There is a possibility of a more marine style setup with a manual switch for 1,2, or both. Not too common but easy to spot if looking around
My two cents, with the takeaway being knowledge of your actual coach is the key.
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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Re: So What charges What in battery land [message #365597 is a reply to message #365581] |
Wed, 21 July 2021 11:19 |
boybach
Messages: 566 Registered: December 2020 Location: Vancouver Island
Karma: 4
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Ok lads, thanks for the info. My setup is standard, the Onan charges the house and the alternator charges both. I have an IOTA 55 converter on my rig BTW.
One more thing - in the standard setup, if one battery is low, will the other try to equalize and bring the other up while drawing itself down a tad?
Larry
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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Re: So What charges What in battery land [message #365603 is a reply to message #365597] |
Wed, 21 July 2021 12:36 |
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Matt Colie
Messages: 8547 Registered: March 2007 Location: S.E. Michigan
Karma: 7
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boybach wrote on Wed, 21 July 2021 12:19Ok lads, thanks for the info. My setup is standard, the Onan charges the house and the alternator charges both. I have an IOTA 55 converter on my rig BTW.
One more thing - in the standard setup, if one battery is low, will the other try to equalize and bring the other up while drawing itself down a tad?
Larry
Larry,
That is exactly what is not supposed to happen. With the OE diode isolator, if one bank is way dead, it may take up charging first because the system can't do both with the standard hardware. This is even worse if you have a combiner.
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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Re: So What charges What in battery land [message #365605 is a reply to message #365581] |
Wed, 21 July 2021 13:57 |
Ken Burton
Messages: 10030 Registered: January 2004 Location: Hebron, Indiana
Karma: 10
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If by two batteries you mean one house and one engine battery, then the answer is they will not discharge each other because the isolator sits between them providing separation.
If you mean 2 house batteries in parallel, this is something you do not want to do. The parallel ones will discharge to the level of the lower one. What is worse is the potential exposure to explosion if one of them shorts just one cell. A better solution is two 6 volt batteries in series for extra storage capacity.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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Re: So What charges What in battery land [message #365611 is a reply to message #365581] |
Wed, 21 July 2021 16:18 |
boybach
Messages: 566 Registered: December 2020 Location: Vancouver Island
Karma: 4
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I was just talking about the house and chassis systems, I just have a single house battery.
Larry
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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Re: So What charges What in battery land [message #365615 is a reply to message #365611] |
Wed, 21 July 2021 21:17 |
Ken Burton
Messages: 10030 Registered: January 2004 Location: Hebron, Indiana
Karma: 10
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OK, then the two batteries are isolated from, each other by the isolator and will the batteries will NOT deplete the charge from each other.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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