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Adding second Battery to 2003 Tahoe

Discussion in 'Chevy Tahoe Forum (GMC Yukon, Cadillac Escalade)' started by BIGREDDADDY53, Mar 11, 2013.


    BIGREDDADDY53 Rockstar 100 Posts

    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. Enkeiavalanche

    Enkeiavalanche Rockstar 4 Years ROTM Winner 5000 Posts

    Why do you need a 2nd Battery? Are you adding a few Mods? Putting in a BIG A/V system? Headrest screens?
  3. Conlan Rose

    Conlan Rose Active Member 2 Years 1000 Posts

    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 [MENTION=52280]nakranij[/MENTION] 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.
  4. PantheraUncia

    PantheraUncia Active Member 2 Years 1000 Posts

    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 - - -

    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 - - -

    Enkei.... Everyone needs 2 batteries..... I know I would never go back to 1; even without a heavy load.
  5. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    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. PantheraUncia

    PantheraUncia Active Member 2 Years 1000 Posts

    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.

    BIGREDDADDY53 Rockstar 100 Posts

    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 ( Thanks for the time. Eric
  8. Enkeiavalanche

    Enkeiavalanche Rockstar 4 Years ROTM Winner 5000 Posts

    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,,,,
  9. CountryXJer

    CountryXJer New Member

    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.

    BIGREDDADDY53 Rockstar 100 Posts

    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) ( 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: Apr 28, 2013

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