Dimming still with extra battery

[footeyo86 10+ year member]

I was told by individuals on here I can hook up an extra battery like in the diagram below.

My lights are still dimming after the install and now I'm being told my system isn't running off the back battery wit hit hooked up like this.

My quesiton

1. Why would someone tell me that it would work that way

2. How do you hook up an extra battery correctly

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[bones22 5,000+ posts]

you dont really need 2 fuses between your batteries.

along with that do the big 3 and see what happens

 

[DB_DRAG_SPL 10+ year member]

I was told by individuals on here I can hook up an extra battery like in the diagram below.

My lights are still dimming after the install and now I'm being told my system isn't running off the back battery wit hit hooked up like this.

My quesiton

1. Why would someone tell me that it would work that way

2. How do you hook up an extra battery correctly

It is hooked up correctly. Possible problems can be that you haven't done the big 3 and the possibility that your alternator isn't sufficient enough to charge both batteries.

And whoever told you your system isnt being ran off of the rear battery is a moron.

 

[bones22 5,000+ posts]

check all your connections as well.

if none of that works may need a bigger alt.

what vehicle and how much power?

 

[DB_DRAG_SPL 10+ year member]

check all your connections as well.if none of that works may need a bigger alt.

what vehicle and how much power?

x2, what size alt is on there now?

 

[footeyo86 10+ year member]

Im not certain. I have a 2002 Lincoln Continental. Everything under the hood is stock besides the battery

 

[iamamp3pimp 5,000+ posts]

I was told by individuals on here I can hook up an extra battery like in the diagram below.

My lights are still dimming after the install and now I'm being told my system isn't running off the back battery wit hit hooked up like this.

My quesiton

1. Why would someone tell me that it would work that way

2. How do you hook up an extra battery correctly

its hooked up right, reason tha tits dimming is because your alt charges at 14ish, and the batts sit at 12 ish

the dimming is the lights themselves running from 14.4 to 12.6

absolutely normal.

if you want to completely get rid of dimming you gotta investg in a H.O. alt, but imo, the 350 that you are gonna pay for that isnt worth it.

just a thought, put a DMM on both batts while the car is on and see if it is the same.

it should be.,

 

[Alpineforever 10+ year member]

you dont really need 2 fuses between your batteries.along with that do the big 3 and see what happens

Better safe than sorry with the two fuses... if it ever happens that his front battery should become completely discharged and his rear battery send to much current t the front you can end up with a lot of fried wire between rear battery and front fuse... I personally have two fuses in my setup... but meh, chances are low of this happening...

 

[iamamp3pimp 5,000+ posts]

but do you need an HO alt.

hell no.

 

[DB_DRAG_SPL 10+ year member]

Better safe than sorry with the two fuses... if it ever happens that his front battery should become completely discharged and his rear battery send to much current t the front you can end up with a lot of fried wire between rear battery and front fuse... I personally have two fuses in my setup... but meh, chances are low of this happening...

x2, it's a little added protection on both ends

 

[iamamp3pimp 5,000+ posts]

Better safe than sorry with the two fuses... if it ever happens that his front battery should become completely discharged and his rear battery send to much current t the front you can end up with a lot of fried wire between rear battery and front fuse... I personally have two fuses in my setup... but meh, chances are low of this happening...

if the front batt is discharged then the rear is as well.
reason for the fuses is in case of a short, fuse will blow instead of battery blowing.

 

[DB_DRAG_SPL 10+ year member]

just a thought, put a DMM on both batts while the car is on and see if it is the same.

unless you're like me, 14.7 on the Optima up front, 12.5 on the rear. That's what you call a smoked G31 Yellowtop

 

[WrenchGuy 10+ year member]

Where are your grounds for each battery? Try to get them on the same plane or close to it.

 

[iamamp3pimp 5,000+ posts]

measure resistance between front ground and rear.

has nothing to do with his issue though, as far as diming.

 

[helotaxi 5,000+ posts]

A weak ground will cause dimming. It causes an excessive voltage drop on the whole system.