Leisure battery wiring question

Discussion in 'Mech Tech' started by Day, Nov 16, 2017.

  1. Day

    Day

    Hi.

    In the first picture.
    Starter on right, leisure on left.
    Is the area ringed in red ok...the positive terminal having no big, thick wire?

    Does the leisure battery have the large thick wires from negative to earth and from positive to.? Surely won't fit to the relay.

    Help appreciated.

    Plus...the black wire which goes into the bus is also small for radio, interior light etc.

    What am I missing...[​IMG][​IMG]

    Sent from my GT-I9505 using Tapatalk
     
  2. my cable from battery to battery and earth are big thick cables the same as you would have, my relay takes the big cables. your relay looks like it would only use smaller cables.
    what relay is it, how big is the fuse rated at..........
     
  3. mikedjames

    mikedjames Supporter

    There ought to be fuses near each battery to protect the wires from catching fire if they short to the bodywork anywhere along their length.

    Ideally thicker wires for lower resistance, ideally with the ends crimped on when they are put in place rather than preassembled so there arent big loops of unused wire.

    And again you might want a heavier wire going off to the leisure battery fuse box.

    But it will work like it is now just it can be done better.
     
    snotty likes this.
  4. Day

    Day

    A 4 pin relay with 15a fuse
     
  5. Day

    Day

    So...
    It would be better having thick wires from leisure battery to relay...and starter to relay...

    Is that right?

    I have on line fuses also to put in the circuits.
     
  6. Your main battery needs much heavier cables to feed the starter motor than are used on the leisure cicuit. I guess it depends on what you want to run off the leisure circuit, but mine has a slit charge relay, fuses and cables good for 30amps max, which then runs into a 4 way fuse box for individual circuits- radio, lights and plug in accessories, none of which draws more than 8 amps. No point in using super heavy cable unless you anticipate the need for a serious sound system I’d say, but your cable looks a bit light duty.

    Check the Vehicle Wiring Products site which gives cable sizes and their current rating.
     
    Day and snotty like this.
  7. Day

    Day

    Thanks.
    I understand much better now.
    I plan running only radio and inertia light and phone charger so don't need heavy duty.
     
  8. My cable from battery to battery is thick and has 40amp fuse I think either side of a voltage sensing relay...
    yours looks like the trigger is from the alternator..
    the reason for big cables is if your second battery is low or drain it gets a hell if a lot of amps and may blow your relay or fuse.
     
    Valveandy and Gingerbus like this.
  9. mikedjames

    mikedjames Supporter

    My setup deliberately has the earth lead on the leisure battery the same diameter as the starter battery earth lead, so I only need one jump start cable to start off the leisure battery.
     
    Day likes this.

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