Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Dual batteries

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 74Chev, Nov 20, 2002.

  1. 74Chev

    74Chev 1/2 ton status

    Joined:
    Sep 19, 2002
    Posts:
    102
    Likes Received:
    0
    Location:
    Oregon
    Does anyone know how the factory dual battery isolator was wired on a 79 Jimmy. When I got the truck it was not hooked up. There is one wire attached to the far right terminal (as you are facing the isolator) which I attempted to trace through the loom and it appears to go to some sort of relay on the driver side fender??? What does this relay or whatever it is on the fender do, there is not one on my 74 so i figured it might have something to do with the isolator. I would like to get it rigged back up but do not know where to and what to connect wires to. I used a marine type Perko switch when I did the dual yellow tops in my 74 which has a winch etc., but figured if there is already a factory setup in the Jimmy why not use it.

    Any advice much appreciated.
     
  2. Sandman

    Sandman 3/4 ton status Author

    Joined:
    Apr 15, 2002
    Posts:
    5,653
    Likes Received:
    0
    Location:
    Pocatello, ID
    I've never heard of a factory isolator on a Blazer. I've seen dual systems but they were hooked directly together. Can you post some pics?
     
  3. imiceman44

    imiceman44 1 ton status

    Joined:
    Aug 5, 2002
    Posts:
    15,160
    Likes Received:
    1
    Location:
    Sacramento, CA
    Like sandman said, factory never offered that option.
    They only had them linked in parallel.
    This is an after market setup, and I can't help you if I can't see it.
    Can you take a pic and email it to me?
    I will help you wire it back the way it was . /forums/images/graemlins/thumb.gif
     
  4. Michael

    Michael 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    1,576
    Likes Received:
    0
    Location:
    Sherman, Texas
    Here is the factory schematic for dual battery setup:
    Batteries
     
  5. mudddog91

    mudddog91 1/2 ton status

    Joined:
    Dec 28, 2000
    Posts:
    471
    Likes Received:
    0
    Location:
    north carolina
    Hey im glad you posted this.I went to a stereo shop the other day to pick up an isolater and the guy that worked there asked me if i wanted to spend a couple hundred dollars or do it the easy and cheap way.Well being a tightwad and a hardcore wheeler im always looking for an alternative way so he told me to use a starter solenoid as an isolater.HUH? I havent been able to figure this one out yet but Has anyone ever heard of this and if so can you explain it to me???
     
  6. imiceman44

    imiceman44 1 ton status

    Joined:
    Aug 5, 2002
    Posts:
    15,160
    Likes Received:
    1
    Location:
    Sacramento, CA
    Well the starter solenoid works, as I have done it before, but it's not the best way.
    The way it works is that you hook it in a way that when the alternator is charging it will engage, but then the batteries would be connected and if there is one that is bad, it will drain the other.
    The isolator has Diodes in it to prevent juice from crossing over.
    You can do that too but then your cost might creep closer if not over the cost of an isolator.
    Now a good way to work with a small isolator that is cheap and use 2 starter relays (I hear FORD relays are better for that) controled by the isolator for more amps with big ass batteries.
     
  7. Michael

    Michael 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    1,576
    Likes Received:
    0
    Location:
    Sherman, Texas
    I redrew a couple of lines that were too light to see the first time. The factory drawing allows the aux batt to charge while the engine is running, but once the truck is turned off the aux battery can power whatever is connected to it and no draining of the main battery will occur. You can replace the realy with a starter solenoid (which is a realy) if desired...most start relays are not rated for continous duty ("on" for extended periods...like driving down the road) so, you might want to check into a upgraded realy if ya wanna go that route. If you have all the factory parts I would connect like in the schematic.
     

Share This Page