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Dual Batteries

A couple of things don't connect black to black, connect the second battery ground to the engine block or frame keeping it as short as possible.

Yes connect the accessories to the second battery and no the wiring for a isolator is not stock.


What accessories are you thinking about wiring in it will give me a better idea what to recommend.


johnd651 said:
I know this may be way old... but I was looking at doing this... I was wondering if anyone has any pics of the parallel setup. I am going red to red (+) and black to black (-) from secondary battery to the primary?

if i was to use the isolated setup... would I have to have everything i wanted to run off of it hooked up to the secondary battery? I looked at the isolator part, and saw it had the two nuts, and it looked like an input for a wiring harness... is it something thats just there dangling in every truck, or is there more to it?
 
07 and later models have a current sensor in the neg cable that goes to ground. The BCM uses the current measurement plus voltage measurement to calculate the battery charge level. This is sent to the ECM, which then tells the alternator how much volatage to put out. The negative side of the second battery needs to connect to the same neg cable that has the current sensor or the BCM will not include the second battery current in the calculation and the alternator voltage will be wrong.
 
zazzmaster said:
The negative side of the second battery needs to connect to the same neg cable that has the current sensor or the BCM will not include the second battery current in the calculation and the alternator voltage will be wrong.
So running neg to neg from battery will not help unless it's directly connected to the cable that has the sensor?
 
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