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Thread: dual batteries

  1. #1

    Default dual batteries

    Does anyone know why my aux. battery in my 2003 silverado keep failing? I've gone through 2 Optima yellow batteries both brand new for that aux. batterty position. Does the alt. charge this battery? Why doesn't it help the main battery when the main battery is low? What does this aux. battery power? What is it for? Can I wire up this thing to the main battery to make it stronger? Any advice, comments, teachings, schoolings would be greatly appreciated for this newby. Thanks

  2. #2


    first things first, is that a diesel motor? Just trying to figure out why you have 2 batteries, and if it's factory. Secondly, there may be a problem with your other battery that is causing the first one to take the load and get killed. For the most part, vehicle batteries should be replaced together, preferably from the same brand, bath, and week of batteries to make sure they are matched. Disalike batteries due to age, brands, etc can cause the other batteries in the bank to prematurley fail... Hope this helps.

    1991 Chevy Suburban 1/2 ton 2WD w/ chevy SBC 350-3/4 ton drivetrain upgrade w/4.10 gears 200K miles
    2005 Saturn ION-2 Stock 277K miles
    1982 Bronco, 1993 Bronco (sold), 1971 M35A2 Deuce and a Half

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