2nd battery wiring? only run positive wire from the front ,or run positive and neg wire to rear battery?

[Jimg]

how are you guys running your 2nd battery setup?

1 Is it best to run a 0 g positive and negative 0 g wire from the front battery to the rear battery

2 or is it ok to just run a single line from the positive to the 2nd battery ,and just ground the rear battery to a spot in the rear

or 3 does it not matter either way

plan on running 2/0 welding cable

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[Ripkon]

I ran 1/0 gauge from the positive and grounded the rear battery to the chassis.

 

[BCotrell]

I just dealt with challenges stemming from my chassis not being a good ground (rubber engine mounts,etc) so If you don’t have a complete loop that includes a good chassis to frame ground your second battery voltage could (may not but could) suffer if you’re only running positive battery to battery. My remedy was front battery to frame ground and front battery to rear battery ground. Second battery to frame would be essentially the same as long as you already have solid front ground to frame. Cost me $20 run of 2/0 welding battery to battery and two extra lugs.