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Dual battery set up in a 1954 M38A1

Discussion in 'Early CJ5 and CJ6 Tech' started by moparman1978, Sep 21, 2009.

  1. Sep 21, 2009
    moparman1978

    moparman1978 Member

    Grants Pass, Oregon
    Joined:
    Jan 29, 2008
    Messages:
    46
    Hi, just asking for input on a problem I have, I have a 1954 M38A1 I am working to operate as a 1955 CJ-5, I have my battery mounted on the fire wall, but I need to mount my oilbath aircleaner on the firewall in the same area, no problem. Then I thought of a good place to place a battery and that is the battery cowl it is still intact on the tub, and I found out that a group 51 battery can fit there, then i thought about if I can place two group 51's in the cowl and run a dual 12v set up being that the old 24v harness is toast andI have a new harness to install that is modern 12v for a early CJ-5. Does any think this could work? would this need an isolator in the cowl , this way the extra battery can support accessory power for winch, or other power accessories, any opinion would be helpful Thanks Mike
     
    moparman1978, Sep 21, 2009
    #1
  2. Sep 21, 2009
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
    Joined:
    Nov 6, 2002
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    4,275
    You could simply run the batteries in parallel with not problem.
     
    w3srl, Sep 21, 2009
    #2
  3. Sep 21, 2009
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Aug 3, 2003
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    I would suggest looking into using an isolator set up such as used in camper vans. It will charge both batteries, but holds one in reserve for emergency starting or whatever. And it could allow one to be a deep-cycle type if desired.

    While using batteries in simple parallel will work, keeping the charge rate just right for each battery individually may not be possible. If one is down, the other can get overcharged, and visa-versa.
     
    PeteL, Sep 21, 2009
    #3
  4. Sep 22, 2009
    panzer

    panzer Super Mod Staff Member

    Columbus, OH
    Joined:
    Dec 9, 2003
    Messages:
    1,245
    I'm doing a second battery set up myself. I'll get a couple of pictures of what I'm
    doing. I got another tray and mounted it on the firewall. I still am using the oil/air
    filter. Plenty of room. Looking to mount an isolator on the fender well. Making a
    bracket. This is the switch/isolator I'm using:

    [​IMG]
     
    panzer, Sep 22, 2009
    #4
  5. Sep 22, 2009
    jflots

    jflots Member

    New Smyrna Beach, FL
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    Sep 30, 2005
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    308
    jflots, Sep 22, 2009
    #5
  6. Sep 22, 2009
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
    Joined:
    Nov 15, 2003
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    I want to get a dual set up as well. I have a marine isolator that is keyed. You can shut off power to both batteries and lock it so it will have no juice. Just need to work on a battery tray that will hold 2 batteries.
     
    jzeber, Sep 22, 2009
    #6
  7. Sep 22, 2009
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    The M38AI "recess" could accomodate an optional 24 volt outlet, for cables to power external equipment.
     
    PeteL, Sep 22, 2009
    #7
  8. Sep 22, 2009
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
    Joined:
    Nov 6, 2002
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    4,275
    Just an idea:

    Rather than mounting that big, clunky rotary switch in the tight confines of an early Jeep, use the aforementioned isolator so that one alternator can charge both batteries but the vehicle will only run off of one. You use the second one for winch, mondo-off-road-lights-from-h*ll, etc. so you can't kill the starting battery.

    Another nice touch is putting a starter solenoid in there with a momentary pushbutton switch so that if the starting battery does go flat you can press the button and temporarily parallel both batteries together to get you going again. As soon as you release the button you are back to separate battery systems charged by a single alternator. Works like a charm!
     
    w3srl, Sep 22, 2009
    #8
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