Dual Battery - Power in the bus

Discussion in ''How To' & 'Handy Hints'' started by Marty, Aug 1, 2008.

  1. syncro

    syncro Well-Known Member

    Messages:
    8,794
    Location:
    Southern Highlands
    D+ is from the alternator. It gives power to the alternator light and to the heater fan relay. It is only energised when the alternator is running.
     
    David H and Mr Beckstar like this.
  2. David H

    David H Well-Known Member

    Messages:
    2,627
    Location:
    newcastle
    Thanks synchro. So what would be the difference other than the initial start cycle delay? How do I get to that position on the alternator to connect to it?
    Cheers
     
  3. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    486
    Location:
    Bateau Bay, NSW
    Ahhhhh, so connecting to D+ will only close the relay when the alternator is charging, which means the deep cycle battery won't be subjected to high current draw when you operate the starter motor (and this is the time it's probably already low on charge after you've been camping using 12v power), and will get charged up initially after engine start but will then be disconnected when full charge is reached. Then, it will only be reconnected when the alternator charges again thus keeping it topped up but not really using it as a power source when driving. Sounds like a good way of setting up the deep cycle battery.
     
    Maxa1967 and David H like this.
  4. David H

    David H Well-Known Member

    Messages:
    2,627
    Location:
    newcastle
    Starter battery is isolated from LH battery right up until key is used. So even if LH battery is empty it cannot empty RH before a start is executed unless wires burn! Whilst key is on & engine running both batteries are being charged.
    Cheers
     
    Last edited: Jun 2, 2017
  5. syncro

    syncro Well-Known Member

    Messages:
    8,794
    Location:
    Southern Highlands
    Which can happen. It happened to me with wiring from a previous owner.
     
  6. syncro

    syncro Well-Known Member

    Messages:
    8,794
    Location:
    Southern Highlands
    Take it from the heater fan relay.
     
    David H and Mr Beckstar like this.
  7. David H

    David H Well-Known Member

    Messages:
    2,627
    Location:
    newcastle
    Hi Synchro,
    Where would I find the heater fan relay position on my bay? Too many bits on the bulkhead to choose from....or is it even there or is it 'inline'?
    Thanks
     
  8. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    486
    Location:
    Bateau Bay, NSW
    I think the heater fan relay is the box up in the top right hand corner of this photo.

    resized IMG_4264.jpg
     
  9. David H

    David H Well-Known Member

    Messages:
    2,627
    Location:
    newcastle
    The only thing on my Rh bulkhead is this P1100942.jpg2.jpg
    Don't understand the writing. The top of it looks like a heat sink. serrated....so it may be a relay.
    P1100943.jpg2.jpg
    Cheers
     
  10. syncro

    syncro Well-Known Member

    Messages:
    8,794
    Location:
    Southern Highlands
    Isn't up near the heater fan?
     
  11. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    486
    Location:
    Bateau Bay, NSW
    Check if the wires go to the heater fan Dave. Or trace wires back from heater fan.
     
  12. syncro

    syncro Well-Known Member

    Messages:
    8,794
    Location:
    Southern Highlands
    That photo is the voltage regulator.
     
  13. David H

    David H Well-Known Member

    Messages:
    2,627
    Location:
    newcastle
    Thanks syncro. I'll go hunt elsewhere tomorrow.
    Cheers
     
  14. syncro

    syncro Well-Known Member

    Messages:
    8,794
    Location:
    Southern Highlands
    Take a photo straight in the engine bay showing the fan.
     
  15. David H

    David H Well-Known Member

    Messages:
    2,627
    Location:
    newcastle
    Hi Phill,
    Is this it? Once you pointed my eye in the right direction I saw it:). Had a Kombi for 38 yrs. Didn't know it was there. Excuse my ignorance but why do they need a relay? Electrical is my weakest field:rolleyes:.
    P1100946.jpg2.jpg
    So the little brown wire with the blue cover?
    Gotta clean that engine bay of pb dust soono_O.
    Cheers & thanks.
     
    Last edited: Jan 14, 2018

Share This Page