Second battery

Can someone please explain to me how do you wire a second battery??? I just picked up a 6 Channel JL Audio Amp. and I want to run a second battery. How do I wire this. Is it power cable to the new battery and ground, or new battery to battery one {Positive to Positve/Negitive to Negitive} running the power cable to battery two or lastly Run both positive wires to the alt and both negetives to the same ground??? I've done all the other speaker and wire connections. This is just my last step and now I''m stuck.

When someone completes that, can they then tell me how to wire 4 batteries? Not to steal your post, but I have some of the same questions. I want to run two perko switches. Thanks.

I would wire the two batteries through a perko. That way if you kill one battery you can switch to the second battery to get the boat started then switch to both to allow the dead battery to recharge.
The same could be done with two perkos. As soon as you conect the charge wire to both perkos you will have a parrallel circuit. Of course there will always be at least two batteries connected (one from each perko) or all four connected so it would almost be easier to just parrallel two sets of batteries together (one set to switch one and one set to switch two).
Parrallel means positive to positive and negative to negative.

I would wire the two batteries through a perko. That way if you kill one battery you can switch to the second battery to get the boat started then switch to both to allow the dead battery to recharge.
The same could be done with two perkos. As soon as you conect the charge wire to both perkos you will have a parrallel circuit. Of course there will always be at least two batteries connected (one from each perko) or all four connected so it would almost be easier to just parrallel two sets of batteries together (one set to switch one and one set to switch two).
Parrallel means positive to positive and negative to negative.
That is how it is done.
In Cole Sanger's case though, if it's for stereo purposes, I'd opt to parallel 3 batteries to one side of the Perko switch, for the stereo, and use the other for starting.

That is how it is done.
In Cole Sanger's case though, if it's for stereo purposes, I'd opt to parallel 3 batteries to one side of the Perko switch, for the stereo, and use the other for starting.
Yes, actually that would be better. No real need for two batteries to start the boat.

When someone completes that, can they then tell me how to wire 4 batteries? Not to steal your post, but I have some of the same questions. I want to run two perko switches. Thanks.
Why two perkos???
I have 4 batts. 3 for the system and 1 in reserve to start and run.
Batt 3 batta are wired together (not sure if the term is parallel or series).
Batt 4 cables connect to batt 3 and those go to batt 2. The neg cable from batt 2 go to ground and pos cable from batt 2 goes to post 2 on the perko.
Batt 1 neg goes to ground and batt 1 pos goes to post 1 on the perko.
The starter cable goes to the common post on the perko. Then the draw comes from whichever battery(s) is selected on the perko switch.
This set up works great for me.
J

Run atleast a 2guage cable from the front battery to the second battery. Get a battery isolator and connect it right next to the battery. That will keep the battery from discharging. Make sure that BOTH batteries are new. If you put a new one with an old one it will bring you problems. TRUST me on this. i know from first hand experience. The isolators are on ebay for about $60. I have one but havent hooked it up. Im running 2 batteries,200 amp alternator and some heavy cable in my denali and have zero issues.
Oh and if your going to run 2 batteries then you will need to upgrade your alternator!!!!!!
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