Dual battery set up

[th3 shifty]

Hey guys.. been searching a lot about the dual battery set up. I’ve decided I want to do this. I have a 96 2dr tahoe, so I already have the side mount for the driver side battery tray, just need the top portion.

Anyway, anyone have experience with doing this mod? From what I read I need to use an isolator, I hear GM makes one. One of my biggest questions is what alternator to go with? I just finished doing the big 3 upgrade with 0 gauge.. but I want an alternator that I don’t have to modify, my wiring is the rectangle plug into the back of the alt if that helps.

 

[justchecking]

What will be the purpose of your dual battery setup? Mine is set up so I can power my camper from my MAIN battery (in the original location) with my secondary battery solely as a backup in case the main battery gets run down or fails. That just happened. My MAIN battery (Diehard Platinum with four year replacement warranty) died dead after 2.5 years. I just flipped the switch to the backup and away we went. The backup is only connected/charged while the engine is running when the switch is in the normal position. The start position switches it in parallel for starting. The system I use is the HellRoaring backup battery system. Easy install.

 

[Eman85]

Are you wanting a dual battery for starting power? Power a camper? An isolator will allow the extra battery to charge and not discharge the main battery so you can power a trailer or other accessories with just the extra battery.

 

[swathdiver]

@intheburbs Bill has done extensive write ups on the TP2 or TP3, can't remember, dual battery set up on his GMT900s.

 

[Doubeleive]

if it's not needed for some external use as noted above you can just run it parallel, nothing extra needed other than a 2nd cable to the starter from 2nd battery and a ground wire.
your existing alternator will work fine
if you are running audio amps or something then you might want to upgrade the alternator 160amp are pretty common, anything higher and you will want to do your homework as to what will work best for you.

 

[bsamole]

I agree with Doubeleive. Years ago I setup a dual battery with isolator using GM parts for the second tray and hold down. However the isolator broke and I just ran parallel cable to the original battery. I believe Doubeleive's idea to run the parallel cable directly to the starter is a better idea. My alternator is stock and I do not run power drawing equipment. Not sure of the benefit in having the second battery without an isolator but it is there.

 

[Doubeleive]

I agree with Doubeleive. Years ago I setup a dual battery with isolator using GM parts for the second tray and hold down. However the isolator broke and I just ran parallel cable to the original battery. I believe Doubeleive's idea to run the parallel cable directly to the starter is a better idea. My alternator is stock and I do not run power drawing equipment. Not sure of the benefit in having the second battery without an isolator but it is there.

extra amp hours and cca's, less likely to come out to no start situation

 

[Doubeleive]

whatever you decide both batteries should match (same model/brand) and be the same age, so don't go get a new battery and pair it up with a old one. get 2 new ones

 

[Doubeleive]

another beni is you can jump start someone else with ease, even if there battery is completely flat lined, the extra juice helps a lot

 

[th3 shifty]

Going to have extra electronics in the truck, flip down monitor, possibly run an Xbox. I also do have a car hauler with lighting and winch..

 

[Doubeleive]

Going to have extra electronics in the truck, flip down monitor, possibly run an Xbox. I also do have a car hauler with lighting and winch..

In that case you might want to install a battery isolator and switch, that way you can you use the 2nd battery alone (like for the winch) when needed and not drain the main battery.
lots of marine applications use isolators so there are plenty of choices out there, tons of them on amazon

 

[Trey Hardy]

Going to have extra electronics in the truck, flip down monitor, possibly run an Xbox. I also do have a car hauler with lighting and winch..

You would probably be fine with just upgrading your alternator or upgrading to a lithium battery that puts out more juice.

ALTERNATORS - MECHMAN - CHEVROLET - Tahoe - Down4Sound Shop

www.down4soundshop.com

Xs power makes some really nice lithium batteries

 

[exp500]

Take a look at the Battery wiring on a 1982 GMC diesel. Simple and effictive. Or you can look at boat/marine wiring. Everyone lately tries to make things like RV wiring... Automatic, too complex and no way to isolate or easily test, with high failure rates.

 

[Regjackson1]

What will be the purpose of your dual battery setup? Mine is set up so I can power my camper from my MAIN battery (in the original location) with my secondary battery solely as a backup in case the main battery gets run down or fails. That just happened. My MAIN battery (Diehard Platinum with four year replacement warranty) died dead after 2.5 years. I just flipped the switch to the backup and away we went. The backup is only connected/charged while the engine is running when the switch is in the normal position. The start position switches it in parallel for starting. The system I use is the HellRoaring backup battery system. Easy install.

What size height of the battery?

 

[justchecking]

Same as the oem battery. Two identical batteries

 

[Pressureangle]

Going to have extra electronics in the truck, flip down monitor, possibly run an Xbox. I also do have a car hauler with lighting and winch..

A couple anecdotes. My '04 Yukon XL is loaded to the gills- Bose system, Entertainment/monitor, electric everything and Sunroof. It has one Group Size 78 battery, which seems sufficient even cranking the 8.1. Spec'd for 145A generator. In any case, your 'down the highway' usage has to fall within about 80% of generator capacity.

My '94 6.5 turbodiesel pickup is spec'd for x2 Group Size 78 batteries due to the huge starter and 21:1 compression ratio. The boxes on the '94 hold a size larger battery, and I have a 12k winch installed so I upgraded all the battery cables with military style terminals and the larger batteries.

Since I have no need for engine-off battery capability, there is no isolator. It's not a bad idea to have one between the tow vehicle and trailer, if the trailer has a larger battery than the small breakaway service battery. If you're going to do sound system competitions or spend long hours in the park with the radio on and engine off, auxilliary batteries and isolator are a must.