Two batteries?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=18962
Printed Date: July 13, 2025 at 11:22 PM

Topic: Two batteries?

Posted By: csorb
Subject: Two batteries?
Date Posted: September 17, 2003 at 7:25 PM

A fellow came into my shop. He wants to load up his nissan maxima. He wants a second battery in the trunk for his four subs, and he says he has two caps he wants installed. (He has a seperate amp for his highs and one for his mids. Where do I put the battery and the caps and how do I wire them?

Replies:

Posted By: italnpimp59
Date Posted: September 17, 2003 at 8:43 PM

ok u need two power distribution blocks for this, one should have 2 inputs, the other can just have one input but it must have at least 3 outputs. so he has 3 amps right? ok the two inputs on the first block are one for the battery under the hood and the other for the second battery. just ground the second battery. the output on that block goes to one of the caps (positive end of course), then just daisy chain to the next positive end of the 2nd cap, and then daisy chain it again to the input of the second block. ground first cap, and daisy chain to the other cap. the three outputs on the second block, go to the 3 amps...and just ground all 3 amps! im pretty sure this is right...someone correct me if im wrong.

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Posted By: Ketel22
Date Posted: September 17, 2003 at 10:08 PM

also wont a bigger alternator be needed? but your explanation looks correct.

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Quad L Handyman services

Posted By: Velocity Motors
Date Posted: September 18, 2003 at 12:56 AM

BTW, if it hasn't already been said, make suer that the battery in the trunk is a dry cell battery and that you vent the gases outside the vehicle. Otherwise there is a possibility of an explosion from built up exhaust gases from the battery. Better safe than dead posted_image

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

Posted By: csorb
Date Posted: September 18, 2003 at 10:40 AM

How would I vent the gases?

Thanks for all the input

Posted By: Velocity Motors
Date Posted: September 18, 2003 at 10:54 AM

If you purchase a Optima battery there are two discs on the top of the battery that have plastic tabs on them. These are venting discs . What I have donein the past is made plexiglass covers for these and used small gauge clear tubing ( air line hose ) and attached them to these plexi discs and ran the hose to the vents in the trunk to the outside of the vehicle.

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA