Way to up my back battery voltage?

[Bobby322 10+ year member]

My front battery is at 13.8-14.0 when my car is at idle, and my back battery is at ~12.4. I have a run of 1/0 from front battery to the back and all the wiring to amp is done in 1/0. I dont have the big 3 done, but I may do it at least in 4 guage for the time being. How can I up the voltage on the back?

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[plugitin 5,000+ posts]

ground in back maybe? Shouldnt be that low in the rear...

 

[TDH Rogers 10+ year member]

batt in the back is proble bad.... the batteries should level out.... what size fuses do you have between batts? are you running an isolator?

 

[Bobby322 10+ year member]

I doubt the battery is bad. havent had it long at all. I have the back battery grounded to a under the seat bolt. I sanded it down, but I dunno if thats good enough. I cant find a ground to use other than bolts to the seat.

 

[WOT]

Dont "find" a ground, make one, or run it back to the front battery, the batteries should be VERY close, my monies on a dying battery, wouldnt be the first

 

[jadon087 10+ year member]

Dont "find" a ground, make one, or run it back to the front battery, the batteries should be VERY close, my monies on a dying battery, wouldnt be the first

aggred make a run from front back to rear and if it doesnt line up i would assume the batt is dying slowly.

 

[skmfkr 5,000+ posts]

thats why i just use 1/0 wire from front to back for power and ground

 

[Bobby322 10+ year member]

I dont have any 1/0 right now and I dont think i have a long enough run of 4 guage to make another run of pos. and a run of neg. from the front. I dont see how the battery could be dying its pretty new.

 

[WOT]

Some batteries are garbage right off the shelf, like I said, wouldnt be the first

You only need 2 feet to make a body ground, sand it good to bare metal, self tap screw or bolt through the body

 

[Bobby322 10+ year member]

Okay im going to try to go make a ground. If this doesnt raise the voltage on it, then idk..

 

[Bobby322 10+ year member]

Just drilled a hole in floor and sanded it down to bare metal and made my ground. Now im at ~13.7 when my truck is on. When its off just sitting both sit at ~12.4. I didnt bother to connect another ground on the outside of the truck to the chassis. I guess my voltage still drops on hard bass hits cause I cant run my ap30001d at 1ohm and crank it. I put my dmm on the back battery when I had the bass hitting and it was all over the place not accurate at all..so I dunno what I drop down to.