second battery ground question.

[blackga 10+ year member]

instead of running a ground wire all the way from the front battery, can i just ground the second battery to the chassis and be done with it???? just would like to know because my room for running 0 ga wiring therew the firewall is limited as hell.

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[lostdaytomorrow 10+ year member]

Complicated answer, but short answer is yes you can ground it back there, but it might not be optimal.

 

[Mr. Slate 10+ year member]

Most people ground in the rear anyway. Find a good point to ground to like seatbelt bolt.

 

[tylork92 10+ year member]

i just drilled a hole in my floor board that was close to my 2nd batt and close to a chasis hole and grounded that way....i look at it the battery up front is grounded to the same chasis so its not gonna hurt anything.

 

[kdicetharappa 10+ year member]

my opinion? ground to the chassis\frame and run a ground all the way back. put your positive and negative leads in a PVC pipe and mount it to the bottom of the car, then have it come up through the trunk. that way you don't have to go through the firewall.

 

[Mr. Slate 10+ year member]

Running a ground to the back is a waste of money.

 

[kdicetharappa 10+ year member]

Running a ground to the back is a waste of money.

not if you're pulling so much current that a run back up front is more conductive than the frame. or if you don't have a full frame car. or if you don't have any good grounding locations.

 

[hispls 5,000+ posts]

So the entire steel frame of a car would somehow have more resistance than a relatively thin 16ft piece of copper wire?

I've been doing multiple batteries for 15 years and I always just ground as close to the battery as possible.

 

[dave_damage 10+ year member]

Yer mom goes to college.

 

[connersdad19 10+ year member]

when running my rear battery i did both...grounded from front bat to back and then to frame...and so on.

 

[kdicetharappa 10+ year member]

when running my rear battery i did both...grounded from front bat to back and then to frame...and so on.

like i said. with electrical if never hurts to have more conductivity.

 

[blackga 10+ year member]

i just drilled a hole in my floor board that was close to my 2nd batt and close to a chasis hole and grounded that way....i look at it the battery up front is grounded to the same chasis so its not gonna hurt anything.

i was thinking the same way. a ground is a ground. the other battery i installed i used a negative run and grounded it also but like i mentioned i dont have the room now.

 

[audiolife 5,000+ posts]

Depends on the chassis, if it is a unibody there is no chassis front to back but rather sub frames. I have seen a few systems not charge properly from picking a bad ground. Takes more than a few seconds to see if the ground is good or bad. If for example you KNOW your alt puts out more than enough power for your system but you check your rear battery and its dropped a few tenths of a volt over a week or a month or even a day you more than likely have a wiring issue. Real simple term to go by in fixing this is COMPLETE the circuit and ground back up front. 0 gauge from the front to the back you should use 0 from back to front.

 

[blackga 10+ year member]

Depends on the chassis, if it is a unibody there is no chassis front to back but rather sub frames. I have seen a few systems not charge properly from picking a bad ground. Takes more than a few seconds to see if the ground is good or bad. If for example you KNOW your alt puts out more than enough power for your system but you check your rear battery and its dropped a few tenths of a volt over a week or a month or even a day you more than likely have a wiring issue. Real simple term to go by in fixing this is COMPLETE the circuit and ground back up front. 0 gauge from the front to the back you should use 0 from back to front.

ok well i can always add that additional ground if i need 2 but i think i will be ok just because were the factory ground is on the primary battery.

 

[YoungBloodM50 10+ year member]

You'll be fine with the short run of ground. You really don't want to rely on a long a$$ ground all the way from the front to the back. It won't hurt to do both, but as long as the short run is a proper ground. You shouldn't have to worry.