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dual battery

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by schmuck, Jan 16, 2003.

  1. schmuck

    schmuck 1/2 ton status

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    i was thinking of putting dual batterys in my truckcan anyone tell me a few things 1st will it put a strain on the charging system 2nd how do you wire it up 3rd should you use equal batteris or can they be a different amp and if so which should you use as the prmary battery /forums/images/graemlins/1zhelp.gif
     
  2. imiceman44

    imiceman44 1 ton status

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    Well one if you do a search on the subject you will get a ton of info.
    Second you can put 2 batteries it will not put a strain on your charging system if your consumption wasn't already.
    You can put different sizes if you use the isolator (a search will tell you what that means)
    Put the High cranking battery as primary.
    For more do a search. /forums/images/graemlins/deal.gif
     
  3. schmuck

    schmuck 1/2 ton status

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    okay did a searh and im thinkig of just connecting the batteries together in paralell any thoughts
     
  4. bigblock454

    bigblock454 Clack Clack Clack Premium Member

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    Parallel will work fine. That is the way the factory Diesels were configured.
     
  5. Sidepipes

    Sidepipes 1/2 ton status

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    Thats the way mine is hooked up, diferent sized batteries, no problem.
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    If they are hooked up in parallel the batteries should be the same size and age. That's what I was told anyways.

    Rene
     
  7. Sidepipes

    Sidepipes 1/2 ton status

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    Its been in there for about two months now. Honestly, they might be the same size, I didn't really care. I was working on the truck and poked a hole in one of the existing batteries. I pulled the battery out of my car and popped it in.
    I'll check it out tonight and see if they are the same size. I would assume the original one in the truck is around 550CCA and I know the out out of my car is 650CCA.
     
  8. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I'm not sure what the exact reason is, but I think it has something to do with how they will draw from the alternator or something. I got a pair of 875 CCA batteries the same age from our parts donor. They spin the 6.2 over very nicely./forums/images/graemlins/thumb.gif

    Rene
     
  9. schmuck

    schmuck 1/2 ton status

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    allright then that is what im going to do it will be the cheap and easy way to get it done /forums/images/graemlins/thumb.gif
     
  10. emoo99

    emoo99 1/2 ton status

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    dual batteries is good, it gonna put a strain on your alternator if you drain them often, but the main thing to do this is to get 2 of the same size, same type batteries, it may work fine for a while but over time if the batteries aren't sperated the bigger one will drain the smaller one, or the newer one will drain the older one so if their differen't it's good to seperate them with a selonoid or a relay so it charges them when the truck is on and disconnects them from each other when the truck is off.. so you can drain one all the way and still be able to start your truck.. , and you can wire them + to + and - to - to doubble the cranking amps and amp hours.. just make sure you have good solid grounds goin from the - terminal to the chassis so they charge correctly. I've been in the competition industry a while and i'm not a rook when it comes to stereo's or charging systems, i have 4 batteries and a 260amp alternator in my 86 blazer.. /forums/images/graemlins/thumb.gif
     
  11. schmuck

    schmuck 1/2 ton status

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    thanks ill remember that
     
  12. bigblock454

    bigblock454 Clack Clack Clack Premium Member

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    Different sized batteries arn't a problem as long as the one with the starter wire is the highest CCA.
     
  13. emoo99

    emoo99 1/2 ton status

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    if the batteries are wired in parallel they could cause a problem in the long run, but only charging problems, you'd end up having to buy new batteries and/or they wouldn't last as long,, i'm looking at it from a bigger perspective though, my old car i put 4 yellow top optima batteries in my car and had a red top under the hood but they were seperated by a 200amp selenoid so the red top disconnected from the yellow tops as soon as i turned my car off.. so i could play my stereo till my crap turned purple and tasted like rainbow sherbert.. but i guess if it's not a main concern or you don't need a "perfect" charging system it would be ok.. either way you do it, it would still work..
     
  14. txbartman

    txbartman 1/2 ton status

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    if your batteries are wired together and not separated, then it doesn't matter where your starter wire is connected. If the batteries are wired together, then the power for starting is drawn from the combinatoin of the batteries, not one or the other.

    If you wire two batteries together, the batteries will equal out their charges. There are three reasons most 4x4 people run dual batts.

    1. Spare battery: If you are out offroad like we are and someone left the lights on over night at camp, or the radio on, or had a bad battery, or your primary battery comes loose and melts on your intake (won't mention any names), and your rig won't start, you can be in dire straits. If you can "flip" over to the spare battery and start right up, youhave been saved. If you had the two batteries wired direct, you would still be in trouble as both batteries would have drained (in the first 3 instances). The second might have kept the lights or radio on longer, bt come morning you are still SOL. Use a solenoid or isolator and the batteries are disconnected when the ignition is off (if wired correctly). They are only connected while the engine is running and supposedly charging versus draining.

    2. Support offroad lights and/or a winch: If you run a lot of offroad lights or a winch, they can quickly drain a battery. If you run these off your main battery and running them in a situation that causes it to drain (idle, low RPM, or engine off), you could be in trouble. Again, if you have a spare to "flip" to, then you are A-OK. Same problem as before if they are wired together. If you really want to be safe, you run your winch and lights and other accessories off the spare battery and leave the primary for the essential engine functions. This way if you run it down, you don't even have to "flip" to start the rig. Again, using an isolator or solenoid still allows for charging when the engine is running.

    3. Extra winching power: There are times when you need to really squeak out every bit of power the winch offers. This means HIGH AMP draw. In this situation, you WANT the two batteries connected to increase the amperage flow to the winch allowing its motor to work. Just be careful not to completely drain it as you have no spare!

    Most isolators will allow for three settings. You can have the batteries disconnected all the time, connected only while the engine is running, or connected with the engine running or not. With a simple three position toggle, you can also wire a solenoid to do the same thing.

    So.... Wiring the batteries directly together may be a cheap, easy alternative. But, it may not serve much of a purpose. A spare battery fully charged but not even wired can help, too. The next step up would be an isolator. These can be purchased for $30-40 at a marine or RV supply place for a 200A unit. The final step would be to get a kit from someone like Hellroaring or WranglerNW. These typically run $100-150. So you make the call, but what's the point of doing something if you don't o it right and the result gains you nothing?
     
  15. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Reason #4 to dual batteries:

    You have a 6.2 diesel under the hood /forums/images/graemlins/thumb.gif.

    Rene
     
  16. schmuck

    schmuck 1/2 ton status

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    well right now the main reason for dual batteries is alot of electronics cb, lights, scanner, tv, radar detector, ect sometimes i run alot of them together and also for more starting power but later i will probobly buy better bateries and a isolater
     
  17. bigblock454

    bigblock454 Clack Clack Clack Premium Member

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    The reason for having the largest (highest CCA) battery connected to the starter is you want to keep that battery with the shortest wire length.
     
  18. schmuck

    schmuck 1/2 ton status

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    ok ill try that because both of my batteries are not the same size
     
  19. schmuck

    schmuck 1/2 ton status

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    ok i just hooked up my other battery in parallel and now it seems like my altinator is not realy wanting to work. any help
     
  20. bigblock454

    bigblock454 Clack Clack Clack Premium Member

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    What the signs that it isn't charging?
     

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