Dual battery set up - will this work correctly?

Zeus78

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Mar 1, 2021
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I found this site while searching for wiring diagrams on a proper dual battery setup. The problem is, most of the links and photos that I am looking for, are long gone since the threads are so old. I'm trying to keep it as simple as possible, so 10 years down the road, if there is an electrical issue, there isn't any confusion, for me, or for anyone else.
So, I pulled a couple of batteries out of an 07 F350 diesel and I've ordered an isolator. My main question is, do I still wire the main battery through the stock solenoid? No diagram I have seen shows the stock solenoid. Take a look at this diagram and let me know if this will work. The red circle I drew is the stock solenoid.

1978 Bronco custom
1972 Lincoln 460 .030
 

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Tiha

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the main battery goes to the starter solenoid like normal.

the diagram you have posted, when the solenoid is activated it will essentially connect the two batteries in parallel.

Which will double the current to the starter OR aux device you are running.

Was that your goal?

I don't see any way to charge the aux battery in that picture, it can be done through diodes to isolate it and not drain them both.

Maybe turn the isolator/solenoid on while the truck is running and not using the aux. that will charge it.
 

Zeus78

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Mar 1, 2021
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Northern KY
the main battery goes to the starter solenoid like normal.

the diagram you have posted, when the solenoid is activated it will essentially connect the two batteries in parallel.

Which will double the current to the starter OR aux device you are running.

Was that your goal?

I don't see any way to charge the aux battery in that picture, it can be done through diodes to isolate it and not drain them both.

Maybe turn the isolator/solenoid on while the truck is running and not using the aux. that will charge it.
I have a 12K winch, on board welder (future), inverter and exterior light bars.
It was my belief that the alternator would charge the aux battery through the isolator, will that not happen with this set up? The alternator would be connected to the main battery and the feed to the isolator, which would be a one way feed to the aux battery, but if that's not how it will work, how would I run it so it will work?
I just want a simple diagram that shows how the 2 batteries, the isolator, the alternator and the solenoid would all work together.
 

Tiha

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Midwest
It will work that way as long as you are buying an actual isolator and not a generic solenoid. It will charge the aux battery.

A generic solenoid will not charge the battery. Some retailers do not understand the difference so as long as you know what you are buying then you are good to go. It will work just like you have it drawn.
 

Zeus78

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Mar 1, 2021
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Location
Northern KY
It will work that way as long as you are buying an actual isolator and not a generic solenoid. It will charge the aux battery.

A generic solenoid will not charge the battery. Some retailers do not understand the difference so as long as you know what you are buying then you are good to go. It will work just like you have it drawn.
Yeah, it's a dedicated isolator, but the alternator will first go to the stock solenoid, where it will disperse to the main battery/isolator/aux battery. I don't see why this wouldn't work, I just can't find a schematic that shows the solenoid being incorporated.

Thanks for the responses
 

Tiha

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Basically all of your wiring is like factory, You are just adding a second battery and connecting it to the positive post of the first battery through an isolator.

Maybe you are looking for a more complicated answer than it is?
 

David D

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Dec 9, 2019
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I worked at an alternator shop for about 5 years before I reached retirement. I have taken many of the fancy dual battery isolators on RV's and replaced them with heavy duty 100 amp continuous duty solenoids to cure the charging and starting problems the seem to develop over time. If a solenoid doesn't work then there are a lot of 12/24 volt diesels out there running on magic.
 

chrlsful

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S. Amherst, MA 01002-1827
check-in w/the mig welder co for their schematic B4 doing the rest of the wrk. That will require a huge (power) alternator and must be in the over all scheme. An inverter (to run a 4.5 inch grinder or whatever else U want for working) needs placed too. To weld U need power/ground that does not feed back into the general operating system of the car. Not sure how the 110 power creation fits in w/this all (or even this, OOML).
 

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