Split charger woes.

Discussion in 'Mech Tech' started by ginger ninja, Mar 29, 2018.

  1. 77 Westy

    77 Westy Supporter

    With the engine off and no load on the starter battery it should be at least 12.6 volts, with the engine running circa 14v or more just after start-up and less as the starter battery charges.

    As I said up there^ the relay to the leisure battery is not the cause of the starter battery being discharged – the relay is doing what it’s supposed to do.
     
    Last edited: Mar 29, 2018
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  2. ginger ninja

    ginger ninja Supporter

    Pkrboo
    Engine off starter 12.45v leisure 13.01v
    Engine on starter 14.15v leisure 12.84v

    Sorry westy 77 you did indeed. Just gotta check wots up now.

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  3. Pudelwagen

    Pudelwagen Supporter

    Have you tried with engine off:
    Measure voltage on starter battery.
    Measure voltage on leisure battery.
    Now put load on leisure circuit, eg turn lights etc on.
    Repeat measurements.

    Just to make sure that your leisure system isn't drawing off your starter bsttery.
     
  4. Yep I would say starter is a bit low and on its way out. Halfords can do a test.
     
  5. ginger ninja

    ginger ninja Supporter

    Hello
    Leisure battery 13.08v no load. And 13.08v under load (same reading). Starter battery 12.28v no load 12 .22 under load.
    P.

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  6. ginger ninja

    ginger ninja Supporter

    Thank you all for taking the time to help me out here. Much appreciated.

    :)
     
  7. Pudelwagen

    Pudelwagen Supporter

    That rather suggests that your leisure electrics are coming off your starter battery instead of your leisure battery.
     
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  8. 77 Westy

    77 Westy Supporter

    When you say underload what load are you applying and where are you applying it?
     
  9. ginger ninja

    ginger ninja Supporter

    Cd player and both internal lights. No engine no mains hook up.

    P.

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  10. 77 Westy

    77 Westy Supporter

    All supplied from the leisure battery? What load did you put on the starter battery?
    Do you actually know what is supplied from which battery?
     
  11. ginger ninja

    ginger ninja Supporter

    No I thought everything worked from the starter battery and it was the split charger's job to take wots needed from the leisure battery to top up the starter battery.

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  12. ginger ninja

    ginger ninja Supporter

    Oh. Doesn't the split charger take wots needed from the leisure battery to top up the starter battery?

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  13. Not how it works.

    The relay allows both batteries to charge while driving but only take power from the leisure battery while camped, if you've wired things to the leisure battery that is.
     
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  14. 77 Westy

    77 Westy Supporter

    The alternator provides the power to charge the starter and the leisure battery, the split charge relay allows the alternator to charge both batteries at the same time when the engine is running. With the engine stopped there is no connection between the two batteries and the stuff you use while camping, lights, water pump, compressor fridge, TV, stereo etc should all be supplied from the leisure battery. Nothing should be supplied from the starter battery so that when you want to start the bus after camping the battery is still fully charged.
     
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  15. ginger ninja

    ginger ninja Supporter

    Ah! Id better get rewiring then. So I assume I should run a wire from the leisure battery through the rear bulkhead to one of those row/box of fuses. And then wire my interior lights dvd and cd player to there. Probably fit it under the rear seat and fit a cigarette lighter socket.

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  16. 77 Westy

    77 Westy Supporter

    Yes, that’s the way to do it^.:thumbsup:
    I thought it was strange that the leisure battery voltage didn’t drop when you put a load on it. In fact your leisure battery is doing nothing whatsoever – just sitting there fully charged – while the starter battery is being discharged by the interior lights, dvd, cd player etc.
    It’s not a surprise that the bus didn’t start after camping at Volksworld.:)
     
  17. ginger ninja

    ginger ninja Supporter

    Thanks so much. It's all making sense now. I might disconnect the wire to the leisure battery for now as it might be in danger of over charging as I drive. I'm guessing the interior lights were wired to the starter battery from new/westy conversion as there wouldn't have been a leisure battery. Not looking forward to rerooting those wires especially the stereo and cab interior light! Might not bother with the latter!

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  18. 77 Westy

    77 Westy Supporter

    Leave it connected, it won’t overcharge.

    Westfalia wired the water pump and the rear strip light from the leisure battery – they didn’t have much else.

    I’ve left the cab light and radio memory on the starter battery but the compressor fridge, rear lights, 12v and USB sockets, water pump and CD/radio all come off the leisure battery.
     
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  19. mikedjames

    mikedjames Supporter

    The earth wire on the leisure battery is not good. If the split charge relay is closing properly the positive ends of BOTH batteries should be around 14 volts and the negative end around 0 volts. Use an earth tag as the negative end of your meter probes somewhere like one just inside the engine hatch.
    Then make sure the voltage on the negative terminal of BOTH batteries is basically 0 volts to the tag on the chassis of the bus when the engine is running.
     
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