No announcement yet.

Help wiring battery isolator. Excitation terminal?

  • Filter
  • Time
  • Show
Clear All
new posts

  • Help wiring battery isolator. Excitation terminal?

    Got a free deep cycle, so I want to install it in the trunk to increase runtime of the carpc+stereo. I just won on ebay a surepower 95 amp diode based isolator.

    Strangely, the isolator has 4 terminals instead of the usual 3 on a diode based isolator. The extra terminal is a "excitation" terminal. I realize that some alternators have some sort of voltage sensing or whatever, which explains the need for this excitation terminal.

    So my question is... how do I find out if my car requires the excitation terminal to be connected? Can I just connect the isolator like normal but leave the excitation terminal disconnected? I am guessing that maybe the excitation terminal will tell the alternator to output a higher voltage to compensate for the voltage drop across the diodes?

    I have a 2002 mazda protege, but couldnt find much info on the stock alternator. The positive end of the battery has two large wires connected. I am guessing one is to the alternator and one is to the electrical system.


  • #2
    hello i as well have a 2002 protege mine is the protege 5 but we both have the same alt. i was wondering as well about the same issue as you just wondering if you went a head and installed the isolator or not

    i believe our alt is only 80 i have a 140v 3 stud isolator made by cole hersee co.

    and have not yet installed the system yet just wondering if yours worked ok.


    • #3
      Wow I made this thread along time ago, but I never did figure out what to connect the "excitation terminal" to, so I just left it disconnected and wired everything up like with a standard 3 terminal isolator and it works just fine.

      The voltage that my batteries sees is a bit lower now though, but if anyone knows if the Protege has some sort of excitation terminal that can be connected, Id love to know.