Installing second battery

[MikeCole89 10+ year member]

So when I first signed up for the site I remember seeing a diagram for hooking up a second battery in the trunk. I did a search can not seem to find it? Just wondering if anyone could make me one up or link me to that thread? Thanks

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[mazzasec 5,000+ posts]

 

[patrick1202 10+ year member]

just positive to positive from both battery's

and ground the negative of the second battery to a good grounding point or ground it to the negative of the front battery

 

[MikeCole89 10+ year member]

Ok so the positive-positive put two fuses, one on each end?

 

[flipside1212 10+ year member]

man u can use 1 big fuse on the main line, thats all i did

 

[MikeCole89 10+ year member]

Alright thanks for the help on last question. If I am going to have two amps in the back with 4 12"s. two subs running off each amp should I still run one amp off the front battery or just run both amps off the battery in the trunk?

 

[hrtbrk1 5,000+ posts]

u mite want to upgrade you alt 2...so i was told...and the big 3

 

[MikeCole89 10+ year member]

yea planned on doing that. just not to sure if i should run both amps off the battery in the back or still run one off the battery in the engine compartment

 

[patrick1202 10+ year member]

Ok so the positive-positive put two fuses, one on each end?

if you were really worried about it i would put two fuse blocks on each end of the run of the wire. closest to each battery as suitable like 10 or so inches. because you have current coming from two different ends and if one side gets shorted out it will stop the flow of power from one battery but the other one could still be shorting out

 

[patrick1202 10+ year member]

run them both from the back

 

[fbi90909 5,000+ posts]

man u can use 1 big fuse on the main line, thats all i did

that's not the point, it's to isolate both batteries from the car incase of an accident or something goes wrong with the batteries.

lets say your power wire is running along the passenger trim floor board right next to the doors. you only have 1 fuse up front.

lets say you get t-boned on the passenger side and the impact snaps that wire in the center. the front portion of the wire leading to the front battery will pop if/when the cable grounds itself out.

the other battery on the other hand not having a fuse will still have an active line. what if it grounded out onto the car? could cause a fire or such.

use 2 fuses to isolate the batteries.

 

[MikeCole89 10+ year member]

Alright thanks alot

 

[geowick07 10+ year member]

You only need to upgrade the alternator if Big 3 and good front battery plus maybe a second battery don't do the trick for you. This is how I upgrade electrical:

1) Big 3

2) Good front battery

3) Good rear battery (if necessary)

4) HO Alternator (if necessary)

 

[patrick1202 10+ year member]

that's not the point, it's to isolate both batteries from the car incase of an accident or something goes wrong with the batteries.
lets say your power wire is running along the passenger trim floor board right next to the doors. you only have 1 fuse up front.

lets say you get t-boned on the passenger side and the impact snaps that wire in the center. the front portion of the wire leading to the front battery will pop if/when the cable grounds itself out.

the other battery on the other hand not having a fuse will still have an active line. what if it grounded out onto the car? could cause a fire or such.

use 2 fuses to isolate the batteries.

i beat you... but you explained it a whole hell of a lot better ha

 

[patrick1202 10+ year member]

or no fusing at all??