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How do I wire for a 12V and two 6V batteries?

October 23, 2014, 07:41:57 am

Come spring I plan on moving the good 8D engine battery over to the 8D chassis battery. My chassis battery has a bad cell and is at 8.7 volts.
I plan on putting a 12V 1075 CCA 7 year warranty battery in for starting and when the 8D goes bad I'd like to put in two 6V deep cycle batteries for the chassis. Right now (2) 8D batteries add up to 360# and going to auto series and 6V golf batteries drops the weight way down.
How do I wire these, or can't I do it? We have the boost switch on the dash, a solar panel on the roof, a "salesman" switch by the door, and a Parallax converter/battery charger wired in.
Also, it seems the alternator is only putting out 12.4 volts whereas before it was putting out 14.3--another problem?

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Re: How do I wire for a 12V and two 6V batteries?

Reply #1 – October 23, 2014, 07:47:34 am

The pair of 6v batteries are to be wired in series,  the + of one connected to the -  of the other.  The result is a 12v battery that can be wired just like any other 12v battery,  using the remaining + and -  posts.

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Re: How do I wire for a 12V and two 6V batteries?

Reply #2 – October 23, 2014, 09:28:36 am

Thanks, Tom. I understand about the series wiring, but am/was concerned about charging--the two 6V batteries at 12V charge rate, along with the 12V battery.

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Re: How do I wire for a 12V and two 6V batteries?

Reply #3 – October 23, 2014, 09:47:45 am

No, when you wire two 6 VDC batteries in series, they become a "12 VDC battery in two separate cases".  So charge then just as  you would a 12 VDC battery. 

You need to diagnose the alternator issue.  Could be as simple as a loose or bad connection on the sense wire, or could be a bad alternator.

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Re: How do I wire for a 12V and two 6V batteries?

Reply #4 – October 23, 2014, 09:48:26 am

You have created a twelve volt battery - with six 2 volt cells in series. Â just so happens that they are grouped for convenience into two batteries of three 2 volt cells each. Â so in effect, your charger sees a nice 12 volt battery

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Re: How do I wire for a 12V and two 6V batteries?

Reply #5 – October 23, 2014, 01:37:46 pm

Hey, Thanks guys!! Duh--the "slightly" above average idiot mentality strikes again!!

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