Charging vehicle battery on EHU?

Discussion in 'Motorhome Chat' started by Touchwood, Jun 9, 2014.

  1. Touchwood

    Touchwood Funster

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    Just been to start the engine as not been run for a few weeks, and the vehicle battery is flat. Always been fine before, even after extended non-use, so either I've got a drain or it's goosed.

    Question is, does the vehicle battery charge when on mains hook-up? I've assumed it did, but now I'm not sure, as I've connected the hook-up and I'm still only getting 7 volts at the vehicle battery - alos I've looked at the circuit diagrams and the vehicle battery isn't shown at all on there.
     
  2. Chas17

    Chas17 Funster

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    Mine does. Autocruise Stargazer. I select vehicle or leisure battery on the electrics panel.
     
  3. Bellini

    Bellini Funster

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    I would summise that yours doesn't, but many do.

    Udo's does, athough I discovered that by accident.

    Jim sells a neat box of tricks that easily enables your main battery to be charged from the leisure batteries, and therefore the EHU. £60 from memory and, I'd say, well worth it.
     
  4. Touchwood

    Touchwood Funster

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    Ah - I've got a Veh/Aux switch on the control panel which enables the habitation 12v to be run from the vehicle battery - logic dictates tht when on EHU this would charge the veh battery if switched to veh?
     
  5. Terry

    Terry Funster

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    Quite possibly but if your engine battery is reading 7.5 v chances are it's goosed --not hurt to try and charge it but be ready to buy new :Wink:
    terry
     
  6. Touchwood

    Touchwood Funster

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    Thanks - I think! If it takes charge and comes up to 13v (or whatever) does that mean it's not goosed? Hate to go off and chance it letting me down, how can I be sure it's OK?
     
  7. SuperMike

    SuperMike Read Only Funster

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    If it went to 7.5v and was there for some days, then into the bin it goes. :cry:
     
  8. Touchwood

    Touchwood Funster

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    I'll get my cheque book out then.......
     
  9. Terry

    Terry Funster

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    hi if it accepts a charge once you take it off charge leave for 24 hrs then take a reading IF it reads around 12.5 ish it's ok -12.7 being fully charged :thumb:FROM MEMORY ABOUT 12.2 IS GETTING 50% DISCHARGED ISH =NEW BATTERY
    TERRY
     
  10. SuperMike

    SuperMike Read Only Funster

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    I'm afraid so. Even if you get the voltage back up and it stays up, it will let you down and the most inconvenient time, very soon. :cry:
     
  11. pappajohn

    pappajohn Funster Life Member

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    correct....but it must be manually switched to vehicle.
     
  12. TheBig1

    TheBig1 Funster Life Member

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  13. GJH

    GJH Funster Life Member

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    Logic doesn't always work I'm afraid, Mike. The circuitry on your van is similar to that on the Autoquest we had - you can run the 12v side from the starter battery but not charge it as it is isolated from the charging circuit. We discovered that when on EHU once and the switch was inadvertently flicked to Veh - flat starter battery in the morning.

    To sort it out I fitted a Battery Charge Manager similar to the one in TheBig1's second link - that's a good price as well, about half what CAK Tanks charge for the same thing.
     
  14. Gromett

    Gromett Funster

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    Being at that voltage will probably have killed the battery, if it isn't dead now it is fatally wounded and is only a matter of time before it expires. You may get lucky and have one of those lucky batteries that survived the experience but I wouldn't want to rely on one after that.

    I know this from experience. I took the chance on it because I had 500Ah of traction batteries in the back as leisure batteries which were able to double up as starter batteries in an emergency. But the battery was skewered and after it let me down for the 3rd time I bit the bullet and got a new one. The symptoms mine had was inability to hold charge for more than 2 days. Provided I drove every day or at least every other day it was fine.
     
  15. chaser

    chaser Funster

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    This is absolutely true , we had this thread a couple of weeks ago we have a similer van to yours, and it does not charge the engine battery wherever the switch is, no way does hookup charge the engine battery , as graham says you can get a battery charger and plug it in to one of your outlets to charge the battery when on hookup but that's the only way that I can see:thumb:
     
  16. Moodybrook

    Moodybrook Funster

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    Veh batt charging


    I second this, I have a similiar van. Despite its limitations and faults I have done this,

    http://www.motts.dsl.pipex.com/BRIDGING FUSE.htm

    IT WORKS A TREAT. I used 10mmsq cable and a fuse (actually a 20A, 12V mcb). Gross outlay £12.

    This also works off my solar panel. Basically you are joining up your Leisure batt. and Veh batt. into one big batt. EHU and solar controller sees my set up as a 12V 330AHC battery
    (Veh batt 110AHC + 2 x 110AHC Leisure batts)

    CAUTION is to remove the fuse/open the mcb, before firing up the engine.

    I am gonna get more abuse for suggesting this however it works !! :thumb:

    PS for use when the van is laid up, on the drive, in storage. When in use the alternator does the business.
     
    Last edited: Jun 9, 2014
  17. chaser

    chaser Funster

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    I have just been thinking more about this, and if you have switched your panel to engine thinking you are charging it , you are in fact doing just the opposite because the hookup is still charging your leisure battery but anything you have on in the van is draining your engine battery with nothing going back in. I suppose you don't need it to charge your engine battery in theory when on hookup as nothing will be running off it if you have your switch to aux.:thumb:
     
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