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HELP! - Battery Question

Discussion in 'Chevy Trucks' started by markq, Dec 14, 2005.

  1. markq

    markq Member
    Messages: 47

    I have read all of the threads about adding dual batteries, and I am going to be adding another battery to my '04 2500HD this weekend or next. The question I have is about the batteries.

    I know that everyone says to hook up the batteries in parallel in order to get the most power (which makes sense), but to make sure that they are the same type and age so that the newer battery wont discharge into the old one. The question I have is, if I have an isolator, then do I still need to have 2 batteries the same age, or will that eliminate the problem. With the isolator, the batteries will only be conected when the ignition is on and the system is charging, so my thinking is that I dont need 2 batteries of the same type/age.

    I know that some will say to just get 2 batteries, but I want to know if I will be ok just getting 1 new one, as the one that I have right now is still in great shape.

  2. Plow Meister

    Plow Meister PlowSite.com Addict
    Messages: 1,174

    The problem with the isolator is the plow will only draw power from the battery on which the plow is attached. In theory that's fine but IMO the main reason to have a dual battery set up is to provide more power to the plow and accessories as a whole. Most new vehicles that are factory equipped with dual batteries do not utilize an isolator. The only benefit you will notice with an isolator is your lights won't dim nearly as much when powering the plow. They may still dim, especially after long periods of plow use but not as bad as without.

    As far as the batteries of same age and CCA goes, it is a good idea to have everything as equal as possible. Batteries can drain each other but it happens so slowly you would hardly notice it in a day or two since the alternator continuously re-plenishes the batteries while the engine is running. Unless your current battery is more than 2 or 3 years old I wouldn't worry about it too much. I would, however, try to match the brand and CCA power.
  3. markq

    markq Member
    Messages: 47

    The isolator will only isolate the batteries when the ignition is off. When I am plowing, both batteries will be connected so that I do have the extra power available for plow, warning lights, etc.

    From my understanding the "new draining to old" problem will only occur if the batteries are conntected without the alternator charging them (ignition off). I just want to make sure that this is correct before I set this up.

    Thanks for the input!!!!
  4. Plow Meister

    Plow Meister PlowSite.com Addict
    Messages: 1,174

    Mark, I'll take your word for it about the isolator but I really don't think that's right. It's been a while since I've messed with one. My memory isn't quite what it used to be. Hopefully someone else will chime in and correct us both:dizzy:
  5. TLS

    TLS PlowSite.com Addict
    Messages: 1,425

    If they are different, they will be stealing charging current from each other.

    Just bite the bullet, go out and buy TWO batteries and be done with it.

    The isolator is just one more thing to go bad IMO.