3.6L ESS Aux Battery Bypass

  1. William Hays

    William Hays Member

    First Name:
    William
    Vehicle(s):
    2019 JLR, 1985 CJ7
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    London, KY
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    What you describe would be a bad day. My post may have been misleading. The only cable I disconnect is the AUX Battery negative. In my career I worked with Standby Battery Systems that weighed over 3 tons. I am definitely concerned about battery fires. Have witnessed first hand what can happen with a fallen tool across the full battery stack output. Seen the handle of a 3/8 ratchet glow red and then disappear in about 1.5 seconds. Looking for a rubber end cap of proper size to slide over the end of the AUX negative lead for a added layer of protection while disconnected.
     
  2. OP
    OP
    Jebiruph

    Jebiruph Well-Known Member

    First Name:
    Jerry
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    #122 Jan 12, 2019
    Last edited: Jan 12, 2019
    Your post wasn't misleading, mine needs explaining. Some mechanics are not familiar with the two battery system. They will remove the negative terminal of the Main battery and assume the system is de-energized. Then they remove the Main battery positive terminal, assuming it is de-energized, and allow it to touch grounded metal. This causes a short circuit and on an unmodified system, blows a fuse. Your modification bypasses the fuses in this circumstance. With the Aux battery negative removed, it's not an issue, but if the Aux negative is reconnected, an uninformed mechanic might cause a problem. I would make sure the Aux negative cable could not be casually reinstalled. Does that make sense?
     
  3. Solidaxle

    Solidaxle Well-Known Member

    Vehicle(s):
    JL 2 door
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    If I put a battery charger on the main battery positive and negative will that be charging both batteries?
    Thank you
     
  4. William Hays

    William Hays Member

    First Name:
    William
    Vehicle(s):
    2019 JLR, 1985 CJ7
    Joined:
    Nov 12, 2018
    Location:
    London, KY
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    Retired
    You make an excellent point!
    I am a prime example. 62 year old 3rd generation Jeep owner that has been driving them ever since I could reach the pedals. I have owned my JLR for less than three weeks. Was not aware of this electrical nightmare. Two days after purchase, I was installing my new Warn Zeon 10S winch. With my background, step one was to lift the battery cable. The day wore on, and after fighting with tightening those inside bumper bolts on the factory steel bumper, I was getting tired. Started to route the DC cables up and behind the fender liner and decided it would be easier if I cut the wheels all the way to the right. Forgetting that I had removed the battery cables, I climbed in and started the vehicle. WTF!!! Spent all night on the internet doing research and finally ending up here.
    This is my first brand new Jeep and I am not use to having other people work on them. Looks like that will have to change. By the time I get the rubber end cap, electrical tape, and zip ties installed over the end of the AUX Battery negative cable, it will be clear it is disconnected for a reason.

    P.S.
    I still own a no rust California body and frame 85 CJ7. Attached is the build sheet.

    DSCN1201 Jeep B.jpg
     

    Attached Files:

    Jebiruph likes this.
  5. William Hays

    William Hays Member

    First Name:
    William
    Vehicle(s):
    2019 JLR, 1985 CJ7
    Joined:
    Nov 12, 2018
    Location:
    London, KY
    Posts:
    18
    Liked:
    11
    Occupation:
    Retired
    The short answer is yes, it will charge both batteries.
     
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