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  1. #1

    Default Adding second Battery to 2003 Tahoe

    I have a 2003 Tahoe LT full load auto leveling roof so no DVD. I want to put one in for my 4 year old. Now I had my battery replaced last Dec. and it was a interstate with 600 CCA so I would like to make this the second one and get the right one for my main. Now I will need some sort of setup to make this work. I was a GM salesmen for ten years and sold mostly new but I forget how the 2500 were setup. Any help to do this job on the cheap would be apreciated. Thanks Eric

  2. #2
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    Enkeiavalanche's Avatar
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    Why do you need a 2nd Battery? Are you adding a few Mods? Putting in a BIG A/V system? Headrest screens?
    08 Z71 Avalanche Mods to date: K&N CAI,Hellwig Swaybars and End Links, Corsa Sport Exhaust, Superchips Programer,IPCW LOF & 3rd brake light and tails, AMI Gas door,Show Hooks and Door locks, Enkei Wheels, with Pirelli tires, StreetScene Bowties, Grant Steering wheel,Muth signal mirrors,SSBC Big Brake kit,Huskyliner Mug gards,Floor mats and Hood shield, McGard Lug nuts and locks, Bedrug, Cervini's Ram Air hood,35watt HID Fog lights, Sylvania bulbs all around ZXE's Highs and Lows, WhiteNight Back up lights,Sirius and HD Radio, SnugTop sitting on deck now Got a Softopper on now,Tempress Boat Hatches.... New Bilstein shocks are on... New Mods coming soon..... X

  3. #3

    Default

    The job wouldn't be cheap because you will need to upgrade the power cables and ground, alternator, get a 2nd battery relay or solenoid, and it is recommended you have 2 batteries of the exact same age and design.

    If you need more power while the truck is running a 2nd battery wont help a bigger alt will. If you really wanna do it right ask @SurrealOne or @nakranij about their dual battery mods. Each runs a different set up Surreal runs two isolated batteries while Nak runs two batteries connected together acting as one much larger battery.

    1996 Chevy Tahoe LT 5.7L V8 4X4 205,000+ miles. Built proudly at Janesville Assembly in Janesville, Wisconsin
    Basic mods: Lights all over, bunch of electrical work, and a couple cooling mods.

    Check out my other mods in My Garage: http://www.gmtruckclub.com/forum/sho...t-Tahoe-4-Door

  4. #4

    Default

    Surreal's dual battery setup is much fancier than mine, but he is also got a much heavier load than what I am putting on the dual batteries too.

    Here is what I have in my 1500:










    - - - Updated - - -

    Quote Originally Posted by nakranij View Post
    Surreal's dual battery setup is much fancier than mine, but he is also got a much heavier load than what I am putting on the dual batteries too.

    Here is what I have in my 1500:









    Oh, one thing I forgot to mention, you want to use 2 identical batteries, it is best to avoid 2 batteries with difference capacities for charging reasons (over charge 1, under charge the other).

    I went with the optima batteries because I have 750 or 775 Cold Cranking Amps..... I try to go over factory spec instead of even or below.

    - - - Updated - - -

    Quote Originally Posted by Enkeiavalanche View Post
    Why do you need a 2nd Battery? Are you adding a few Mods? Putting in a BIG A/V system? Headrest screens?
    Enkei.... Everyone needs 2 batteries..... I know I would never go back to 1; even without a heavy load.

  5. #5

    Default

    I won't get into what I'm running unless you're thinking about 250-300amp loads or higher. (I'm set up for a winch that can make those kinds of demands when the winch line gets stuck on something.)

  6. #6

    Default

    The general parts list for my setup is:


    • 2 x new batteries
    • 6 x battery post connectors
    • 2 x 80 amp fuses
    • 2 x 80 amp fuse cases
    • 4 battery terminal ends (4ga or larger)(to crimp on to new battery cables that you are going to make)
    • 10ft of battery cable in red plastic/pvc coating (positive) (4ga or larger)
    • 10ft of 10ft of battery cable in black plastic/pvc coating (negative) (4ga or larger)


    As far as the wire you choose, the sky is the limit..... 4ga being the cheapest you would want to use.

    Half my cables are 4ga. The important ones are 1/0 aut. 1/0 aut cable goes for about $3.50/ft - $4.50/ft. so that is where the cost starts moving up.

  7. #7

    Default

    Thanks for thie info and the list. I have a battery that is not the same as I would put in. I was sold a interstate 600CCA. If I understand things That battery is no good. how do I check for the high output Alt. Great pic's, I do plan on some heavy bass units with another amp, plus a DVD for my sick little one (http://hannahdayfoundation.com/) Thanks for the time. Eric

  8. #8
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    Enkeiavalanche's Avatar
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    I like to go with one of the best out there.. I've used and sold others and Ohio Gen is still the best Not cheap but long lasting and proven,,,, http://www.ohiogen.com/
    08 Z71 Avalanche Mods to date: K&N CAI,Hellwig Swaybars and End Links, Corsa Sport Exhaust, Superchips Programer,IPCW LOF & 3rd brake light and tails, AMI Gas door,Show Hooks and Door locks, Enkei Wheels, with Pirelli tires, StreetScene Bowties, Grant Steering wheel,Muth signal mirrors,SSBC Big Brake kit,Huskyliner Mug gards,Floor mats and Hood shield, McGard Lug nuts and locks, Bedrug, Cervini's Ram Air hood,35watt HID Fog lights, Sylvania bulbs all around ZXE's Highs and Lows, WhiteNight Back up lights,Sirius and HD Radio, SnugTop sitting on deck now Got a Softopper on now,Tempress Boat Hatches.... New Bilstein shocks are on... New Mods coming soon..... X

  9. #9
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    While not to be contradictory to the other posters, IF a battery isolator is used between the alternator and the batteries, size/capacity is not an issue. All other advice is spot on.
    1997 GMC Yukon, 5.7, 4L60E, 115,000, Dual batteries, Jet power programmed, K&N air filter.

    Self jump start capability, custom trailer wiring.

  10. #10

    Default

    Hi Guy's: I have one more question. Will my highoutput alternator hold up to charging two batterys? And yes I wanted to put in DVD into the headrest for my sick 4 year old ( has Cancer) (https://fundrazr.com/campaigns/8RUPa). So I will start picking up some parts and should take me a few months, but will my Alt. do the job? does anyone know.
    Thanks, Eric
    Last edited by BIGREDDADDY53; 04-28-2013 at 04:34 PM.

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