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Split charge Relay and power drain

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  • Split charge Relay and power drain

    Hi

    I had an SV24 with a DC/DC PSU from MGPower and ran a 600w AMP @ 30 AMP.

    I now have a regulated C134 EPIA-M and run it off the same system, i.e. a second battery in the boot/trunk. The problem I have is that the PC and AMP on together will drain the battery in 20 minutes flat. I can only surmise that the relay is not charging the battery. I get 14.3v at the main battery terminal and going into the relay but ony 12.3v at the second battery terminal on the relay and on the second battery terminal.

    The relay has

    Power In from main battery
    Power Out to second battery
    Fridge Power Out
    Ground
    Ignition light

    When I take a reading off the ignition wire it only reads between .1 and .15 of a volt, I thought that this may be the cause?

    Basically the voltage off Power out to the second battery seems to be just the voltage from the battery and when I power up the PC it just steadily drops about .1 volt every 40 ish seconds

    I have searched the forum on split charge relays and found some interesting links and coments made on the "Black Art" of Lead Acid battery charging

    Any help welcomed
    Lilliput 8", C134 EPIA-M 900 (Black), A1-ITX, 256 Mb RAM, 40 Gb HDD, DVD, 802.11g, mini keyboard

  • #2
    Sounds a bit too technical for me, but..... I don't suppose you have any pics of your set up do ya...?? I wanna Prelude myself...
    In da club....

    ALIZEE WANTS YOU.....

    (\__/)
    (='.'=)
    (")_(")
    Bunny's first poo
    __ U

    Comment


    • #3
      Originally posted by Spaghetti
      Sounds a bit too technical for me, but..... I don't suppose you have any pics of your set up do ya...?? I wanna Prelude myself...
      I do but they are of the old setup, I had an sv24 and a 10.4" screen but I got sick of the size of the screen and the space that the sv24 took up

      http://www.btinternet.com/~jonathan_porter

      The site will be updated as soon as I solve this power issue!
      Lilliput 8", C134 EPIA-M 900 (Black), A1-ITX, 256 Mb RAM, 40 Gb HDD, DVD, 802.11g, mini keyboard

      Comment


      • #4
        That's a lotta wires!
        In da club....

        ALIZEE WANTS YOU.....

        (\__/)
        (='.'=)
        (")_(")
        Bunny's first poo
        __ U

        Comment


        • #5
          It definately sounds as tho the second battery is not being charged. If you could draw a diagram of how it is wired up I will be able to help you. Obviously your alternator is working because you have 14.3v at your main battery. If you have wired it up correctly, when the car is running you should have about 14V (varies due to resistance in wire from alternator to the back of the car.) at the second battery.

          My first suggestion is double check all your wiring.
          Never let the truth get in the way of a good story

          Comment


          • #6
            Originally posted by Spaghetti
            That's a lotta wires!
            There's a lot less now
            Lilliput 8", C134 EPIA-M 900 (Black), A1-ITX, 256 Mb RAM, 40 Gb HDD, DVD, 802.11g, mini keyboard

            Comment


            • #7
              Originally posted by meddler
              It definately sounds as tho the second battery is not being charged. If you could draw a diagram of how it is wired up I will be able to help you. Obviously your alternator is working because you have 14.3v at your main battery. If you have wired it up correctly, when the car is running you should have about 14V (varies due to resistance in wire from alternator to the back of the car.) at the second battery.

              My first suggestion is double check all your wiring.
              Thanks for this. Its a bad diagram but it gives the idea The wire to the rear battery is a heavy guage and about 2 metres

              I don't know what else to try at this time.
              Attached Files
              Lilliput 8", C134 EPIA-M 900 (Black), A1-ITX, 256 Mb RAM, 40 Gb HDD, DVD, 802.11g, mini keyboard

              Comment


              • #8
                Originally posted by slarty
                Thanks for this. Its a bad diagram but it gives the idea The wire to the rear battery is a heavy guage and about 2 metres

                I don't know what else to try at this time.
                It should be wired up as shown in the pic below. I have drawn in the connections for a standard bosch type auto relay, but you should be able to figure it out if you are using something else. It sounds as tho you have the relay wired up incorrectly. Any more dramas let me know.
                Never let the truth get in the way of a good story

                Comment


                • #9
                  Originally posted by meddler
                  It should be wired up as shown in the pic below. I have drawn in the connections for a standard bosch type auto relay, but you should be able to figure it out if you are using something else. It sounds as tho you have the relay wired up incorrectly. Any more dramas let me know.
                  85 does go to ignition on but it goes to the ign on the head unit loam. is .1v enough to switch the relay. Also does the relay switch immediately to charge the second battery as it has the ignition on.

                  Thanks for the help!
                  Lilliput 8", C134 EPIA-M 900 (Black), A1-ITX, 256 Mb RAM, 40 Gb HDD, DVD, 802.11g, mini keyboard

                  Comment


                  • #10
                    most 'ignition' inputs need 12v to trigger. sounds to me like that's the culprit
                    My JeepPC Install

                    "there are no stupid questions, just stupid people."

                    "it's been agreed the whole world stinks so no one's taking showers anymore"

                    Comment


                    • #11
                      Originally posted by shakes
                      most 'ignition' inputs need 12v to trigger. sounds to me like that's the culprit
                      Nice one I'll find a new input ...hmm
                      Lilliput 8", C134 EPIA-M 900 (Black), A1-ITX, 256 Mb RAM, 40 Gb HDD, DVD, 802.11g, mini keyboard

                      Comment


                      • #12
                        what is the part number for your relay? just curious
                        My JeepPC Install

                        "there are no stupid questions, just stupid people."

                        "it's been agreed the whole world stinks so no one's taking showers anymore"

                        Comment


                        • #13
                          LUCAS 33RA associated documents XXB464

                          I'm going to try and work on it next weekend... the keyboard drain is enough to drain the battery overnight... I think I need some kind of intelligent circuit here. time to start searching the forum
                          Lilliput 8", C134 EPIA-M 900 (Black), A1-ITX, 256 Mb RAM, 40 Gb HDD, DVD, 802.11g, mini keyboard

                          Comment


                          • #14
                            as Shakes said, you need 12V across the relay to get the relay to click (probably about 8V min). Getting 12V from the ignition on from your head unit should be enough to make the relay change contacts. Make sure the other side of the coil for the relay is going to ground. The relay is definately the problem, either the realy itself or the wiring for the coil in the relay (terminals 85 and 86)
                            Never let the truth get in the way of a good story

                            Comment


                            • #15
                              [/COLOR]
                              Originally posted by meddler
                              as Shakes said, you need 12V across the relay to get the relay to click (probably about 8V min). Getting 12V from the ignition on from your head unit should be enough to make the relay change contacts. Make sure the other side of the coil for the relay is going to ground. The relay is definately the problem, either the realy itself or the wiring for the coil in the relay (terminals 85 and 86)
                              [COLOR=Black]

                              When the 12v comes from IGN on is it a perminent on and therefore a perminent signal to the regulator to charge the second battery. so when Ignition is off the relay disconects on allowing the rear battery to discharge. Excuse the basic theorising, I'm clearing this up in my head.
                              Lilliput 8", C134 EPIA-M 900 (Black), A1-ITX, 256 Mb RAM, 40 Gb HDD, DVD, 802.11g, mini keyboard

                              Comment

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