Engine battery losing charge

Discussion in 'Motorhome Chat' started by maz, Jul 23, 2011.

  1. maz

    maz Funster

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    Normally my engine battery sits at 12.8v when parked up and doesn't shift from this figure. But over the last few days it's been noticeably dropping when parked up. This morning it was down to 12.4v after 3 days parked. :Sad:

    I drove the van over to ATS this morning but the battery tested fine. So presumably something is causing the battery to drain down but I don't know what. I haven't been doing anything different with the van to usual. Has anyone any ideas what I should be doing to work out what is wrong? Thank you.
     
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  2. acting_strange

    acting_strange

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    Sometimes it can be 'back feeding'through the alternator...

    If you have any electrical knowledge....you could rig an amp meter is series with the battery to measure any current drop and then take out fuses until the drop disappears. This then would tll you what is causing your problem to within an area..
     
  3. maz

    maz Funster

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    Thank you. But if I have limited electrical knowledge and no ammeter? ............... :Blush:
     
  4. scotjimland

    scotjimland Funster Life Member

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    If nothing has changed then I would put it down to an ageing battery .. it may well test ok but has lost some of it's youthful vigour .. how old is it ?
     
  5. rainbow chasers

    rainbow chasers Read Only Funster

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    After market stereo? Usually the culprit, as some demand poower even when 'off' - the drain can be surprisingly high. You can measure with a voltmeter.

    To do this, take a feed off the live after turning everything off and waiting twenty minutes. Use the hab door, and not the front....the vehicle needs to 'go to sleep'

    If you need to go for a full drain check, let me know and I'll tell you how to do it.
     
  6. maz

    maz Funster

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    Age unknown, and because of its location (squashed into back of A class engine compartment) impossible to get at to read any labels that might be on it. :Sad: Having said that, it still started easily first time when reading 12.4v ..........
     
  7. maz

    maz Funster

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    Stereo hasn't been used since I got the van in March. I took the front off and put it in the glove box 2 days after I got it. I like to listen to all the noises the van makes going along, so I can hear if something's about to drop off! :BigGrin:
     
  8. scotjimland

    scotjimland Funster Life Member

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    so, possibly the original, how old is the van .. ?

    we can assume it's charging as it's starting the engine ok, but doesn't hold a charge ..

    Still points to an ageing battery ... personally I would replace it unless you know it's less than three years old, but even if so, it may have had a hard life and need replacing.
     
  9. JJ

    JJ Funster

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    I believe the battery has passed a test and has dropped only 0.4 volts in three days... Is this a sign of a failing battery or maybe some small drain from something that didn't do so before?

    I understand that to change the battery on this model is a major bit of business... it would be a shame to go to the trouble and expense to fit a new battery only to still have the small draining continue...

    JJ :Cool:
     
  10. scotjimland

    scotjimland Funster Life Member

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    You may well be correct JJ .. but distance diagnosing is to say the least difficult, I am only going on the info provided by the OP..
     
  11. maz

    maz Funster

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    Van is coming up to 6 years old - have no means of knowing if battery has been replaced before. But why would it need replacing if the ATS test showed the battery was good? :Confused:
     
  12. scotjimland

    scotjimland Funster Life Member

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    I absolutely appreciate what your saying .. but without physically checking I can't give an answer.. from what you describe about it's location I doubt it's ever been checked or given any TLC ..

    To establish whether the drain is caused by a parasitic load or if it's just old age would require further testing which can't be done from an armchair.. The only way to test for a parasitic load is to remove the negative cable from the battery and connect a digital ammeter between the battery and the cable.. it should read 0.000 amps

    Bear in mind, clocks, alarm systems, radios etc all draw a very small current that will eventually flatten the battery no matter how well it's charged and an old battery will be less capable as it ages, despite testing ok, batteries lose performance over time.. some last 4 or more years .. others can fail in 6 months or less if abused.
     
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  13. Havewheelswilltravel

    Havewheelswilltravel Read Only Funster

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    I had much the same problem after a few days battery voltage dropped and never had the problem before checked batteries swooped them around still loosing charge, just happened after 2 weeks needed something out of a locker opened locker and light was on found the switch was faulty replaced switch and all ok now.

    Hope it's something as simple for you.

    Alan
     
  14. EJB

    EJB Read Only Funster

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    Your statements suggest that you do not have a security alarm fitted???
    If you do have an alarm, and it is armed, it would normally run a vehicle battery down in a few weeks........the plot thickens:Cool:
     
  15. maz

    maz Funster

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    Hi Alan. I hope it is too. I've checked every switch I can think of, but they've all been off. :Sad:
     
  16. maz

    maz Funster

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    Do they?? :Confused:

    No, I do have an alarm fitted (VanBitz Strikeback), but that's been there for over 2 months without causing any noticeable drain down. I use it most nights but have never noticed any difference to the voltage reading whether it's been on or not.

    My plot is quite thick enough already! :Wink:
     
  17. maz

    maz Funster

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    Was going to try this - Heyuplad is here with a multimeter - but it's proving impossible to get onto the wee bolt to disconnect the negative. :RollEyes:

    I've found an auto electrician listed about 8 miles away so think I will be phoning them on Monday to check everything out .............
     
  18. Jaws

    Jaws Funster Life Member

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    The battery is proly past its sell by date.. At 6 years old you should consider replacing it any way...

    What a lot of people miss is the fact that a battery that is past its prime will also put a strain on the charging circuit of the vehicle.. The alternator will be working hard trying to bring the battery up and KEEP it up to its natural gassing voltage of 13.8v

    But in all honesty .. I do think you are perhaps being a bit paranoid.. If everything is working ok why worry :Smile:

    A battery can change its quiescent voltage with all sorts of things.. temperature being the most obvious but an odd one is air pressure ! ( I did know the reason but having done the course on lead acid cells some 40 years ago I am blowed if I can remember !! )
     
  19. buttons

    buttons Funster

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    This is a false economy, get the bat changed and check the negative cable from the battery before connecting it. You know it makes sense. :thumb:
     
  20. maz

    maz Funster

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    I don't know that the battery is 6 years old. Although with the difficulty to get at it, replacement is probably something that previous owners would have delayed as long as possible. If I could be bothered to go outside and open the bonnet up yet again, I would take a photo to show you just how inaccessible the ****ing thing is! I did consider replacing it - that's why I took the van over to ATS in the first place. They tested it and said it was fine.

    If keeping an eye on things and hoping to avoid a potential failure is paranoid, then I'm certainly paranoid and glad of it! :BigGrin:
     
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