This may help explain things.
http://www.hellroaring.com/4wheel.php
Nice write up on dual batteries. I used their system in my LJ, worked very nicely.

 

The only higher output alternator I know of is going to cost you a lot. It's part of the premier power welder. ( premierpowerwelder.com ) But you do get an on-board welder with it. You could take it to an alternator shop and have it rewound.

I only know of one dual battery tray for the JK
The Mountain Off-Road Enterprises (M.O.R.E.) Dual Battery Tray
https://www.jk-forum.com/forums/modified-jk-tech-2/press-release-m-o-r-e-jk-dual-battery-tray-jk-dead-pedal-74083/

I've heard others were going to make them, just have never seen any available beside the M.O.R.E.

 

this may be stupid..but.....where else can you put the second battery...the "trunk"....i have been wanting to do this for awhile but im not sure if thats possible... i like the dual battery setup for under the hood but as it is its already tight ...can the second one get too hot?..

 

You can put it in the trunk if you find smaller batteries. You can also enlarge the trunk for regular batteries. And the cabling to do it right would cost a lot.

A battery can get too hot. The same reason as when you heat a dead battery it will give you some juice, will cause a functioning battery to deteriorate eventually loosing it's ability to hold a charge.

Unless you have a reason to put the second battery in the trunk, I would suggest you go with the battery tray. It's cheaper. This is comming from a person who has two batteries in the trunk. But that's because I have plans for the space the original battery was located.

 

ok that makes sense..and i always think everything would be cheaper..until i start it..soo thanks for the advice lol

 

Runnin them in parrallel AIN'T a good idea. Although you do retain 12 volts, you double the amperage. I sure as hell wouldn't wanna be puttin all that through my computer and sensors. Use an isolator.

 

A load draws what a load draws, regardless of the available energy. The computer or sensor would need to go bad to take advantage of the increased potential engery - assuming the fuse doesn't go first. If, on the other hand, you have a malfunction that a fuse doesn't catch (say a shorted unfused winch cable) you get to watch the cable weld itself to whatever it is shorted to with much more gusto!

Yes - use an isolator. If nothing else you still get to try to start you Jeep once you put the fire out.

 

X2 on what AZJeeper said. All you're doing is increasing the available amps.

I run two in parallel and have been for a long time. I also run a Hellraoring Isolator/Combiner to a single backup battery.

One battery is enough to weld anything on your jeep with a short. Two batteries will just do it faster

1500 CCAs in the back


750 CCAs as a backup up front. The hellraoring is still on a bracket I made to sit on top of the stock battery. I'm going to end up flush mounting it to the fire wall.

 

I think that is officially the most battery power I've ever seen in a JK!

Just think, if you ran a Benchmark tray, you could have 5 batteries!


John @ Benchmark

 

That was the lamest sales pitch I ever heard......but pretty damn funny.