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 > Can I charge the house battery with the engine alternator?

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Ed_Gee

Central Oregon coast

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Posted: 11/11/22 04:06pm Link  |  Quote  |  Print  |  Notify Moderator

bobndot wrote:

12v vs two 6v batteries

Just keep in mind that joining two 6v batts will keep the amps the same, where by joining two 12v batts, the amps will double.


The above is misleading, and possibly erroneous. The capacity of a quality GC2 Six volt battery is generally around 220AH, where the capacity of a good 12V battery is around 100AH ... so you will end up with slightly more capacity with the heavier duty two 6V batteries anyway.


Ed - on the Central Oregon coast
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enblethen

Moses Lake, WA

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Posted: 11/11/22 04:19pm Link  |  Quote  |  Print  |  Notify Moderator

The relay that you found often is powered by a three-position center off rocker switch behind the driver. one position is momentary for aux start function other position is for holding relay in for charging.


Bud
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bobndot

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Posted: 11/11/22 04:46pm Link  |  Quote  |  Print  |  Notify Moderator

Ed_Gee wrote:

bobndot wrote:

12v vs two 6v batteries

Just keep in mind that joining two 6v batts will keep the amps the same, where by joining two 12v batts, the amps will double.


The above is misleading, and possibly erroneous. The capacity of a quality GC2 Six volt battery is generally around 220AH, where the capacity of a good 12V battery is around 100AH ... so you will end up with slightly more capacity with the heavier duty two 6V batteries anyway.


Some people think the 220 6v will give them 440 amps at 12v . All i am saying is a GC-2 at 220 amps is still 220 amps when adding the 2nd GC-2.
However, if you add two 100amp 12 v batts together the amps double to 200 amps but keep the 12v supply to the rv.

JaxDad

Greater Toronto Area

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Posted: 11/11/22 05:53pm Link  |  Quote  |  Print  |  Notify Moderator

Hmmmm…. 2 pages of almost entirely wrong answers.

It’s a 1988 rig, it ran an old school continuous duty relay, AKA a Ford starter relay, on the drivers fender. One heavy lug to the alternator, one heavy lug to the house battery and the light lug goes to an ‘engine on’ circuit.

When you start the chassis the alternator is connected to the chassis AND house battery(s), when you shut off the engine house and chassis batteries are separate.

Any auto parts place $20…….

enblethen

Moses Lake, WA

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Posted: 11/11/22 06:14pm Link  |  Quote  |  Print  |  Notify Moderator

In that era, there was no electronics operating the relay. It was controlled manually by rocker switch.

BarabooBob

Baraboo, WI

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Posted: 11/11/22 08:37pm Link  |  Quote  |  Print  |  Notify Moderator

I had a 1988 Damon (built on a one ton Toyota chassis.) That unit had a solid state battery isolator from the factory. It worked great until it didn't work at all. I replaced it with a constant duty solanoid type isolator. It then worked great again.
The shortfall of my system was the 60 amp alternator. It could barely keep the chassis battery charged when the headlights were turned on. A conversion to a 150 amp alt gave better charging but took extra power to spin the alt, something that my 110 hp engine didn;t have an abundance of.

I forgot to say that from what I have heard, if you want to add a second battery to your coach, the batteries should be installed together as a pair. Adding a new battery to and old battery will give you two old batteries because the old will draw down your new much faster.


Bob & Dawn Married 34 years
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pianotuna

Regina, SK, Canada

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Posted: 11/11/22 10:32pm Link  |  Quote  |  Print  |  Notify Moderator

Much better to use a dc to DC charger. I have a 20 amp unit and love it.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

heyobie

Maryland

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Posted: 11/13/22 03:02am Link  |  Quote  |  Print  |  Notify Moderator

Thanks guys for all the help and education and support. I'm smarter than I was and Crush (that's my RVs name) is now better off.

So I decided to test the solenoid now that I understand what is supposed to happen. So I gave the small post 12 volts and it worked just fine. I redid the wiring and cleaned all contacts and posts. There was some corrosion and bad wiring which caused the solenoid not to function. After I put it all back together I got it working as designed. Victory. I just need to add a toggle switch so I can control when it charges the house.

I went to Sam's Club and got a second 12 volt marine/RV battery to match the one that I had first and I will be wiring them in parallel so that I can get ready for my big trip.
While it is a 1988 it only has 40,000 miles on it of which I have put on 10,000. We are planning to go from Maryland to Northern Florida and cut across the Gulf Coast for about a month this winter. So I will be better able to handle the cold than I was with just 1 battery and no house charge as I drove.

Again, thanks for the help.

pianotuna

Regina, SK, Canada

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Posted: 11/13/22 11:09am Link  |  Quote  |  Print  |  Notify Moderator

heyobie wrote:



I went to Sam's Club and got a second 12 volt marine/RV battery to match the one that I had first and I will be wiring them in parallel so that I can get ready for my big trip.


Be sure to wire the batteries in a balanced manner.

heyobie

Maryland

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Posted: 11/13/22 11:49am Link  |  Quote  |  Print  |  Notify Moderator

Pianotuna,

Not sure what you mean by balanced manner?

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