How do I test the Hab Batteries

Discussion in 'Tech/Mech General' started by emmitdb, Jun 15, 2016.

  1. emmitdb

    emmitdb Funster

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    Greetings All,

    Just back from France.

    While we were there we noticed that as it was getting dark the gauge for the Hab batteries showed a decline over what we have come to expect. Nothing alarming but a definate falling off on the gauge without any usage.

    I suspect that one (maybe both) of the two hab batteries is on the way out.

    History. We have had the 'van for two years. One of the batteries was used before it was put in there and the other was put in by the seller and I believe that that one was new at the time. So one is older than the other. they are 110's fitted in parallel and supported by an 80w solar on the roof.

    In a weeks time we head for Bagwell Farm and I don't want the batteries to be a problem.

    Whilst I understand the fundementals of batteries I have no idea on how to test them.

    Could someone on here tell me how to go about it.

    I appreciate that I MAY have to put my hand in my pocket for a pair of new ones but I would appreciate the opportunity of testing them before I need to splash out.

    As usual thanks for any positive contributions.
     
  2. scotjimland

    scotjimland Funster Life Member

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    They can be tested with a battery drop tester .. basically it it puts a load on the battery while measuring the voltage drop .. any battery supplier can do this for you ..

    but from what you say it looks like they are on the way out.. time to get hand in pocket..
     
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  3. bubble63

    bubble63 Funster

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    jim is right to an extent, I have a battery drop tester and my 'iffy' batteries pass the drop tester....... but they don't perform as they used to
    I think the only way to test them properly is to fully charge them and then put a known load on them and time the discharge.
    ie a 110a battery is only really capable of give around half its capacity i.e. 55A so if you put a 5 amp known load on the battery should be able to deliver 5a for 10 hours before it drops below 12.0 v

    I like this chart
    [​IMG]
     
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  4. ericroy

    ericroy Funster

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    How about the cheap and simple solution of checking the electrolyte specific gravity with a hydrometer? This will identify any dodgy cells more certainly and far more economically than the hi-tech and expensive battery tester.

    OK, now I have searched on-line I know the answer - hydrometers are no longer easy to buy. Halfords and the like would rather sell you a £100 battery tester than a few pounds worth of rubber and glass in the form of a hydrometer! This is progress....?

    But on ebay you can find a hydrometer for under a fiver and watch a YouTube video on how to use it (if you need help) :D
     
  5. Gizmouk

    Gizmouk Funster

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    The only way to test batteries is to do a discharge test.
    For a habitation battery, it can be as simple as apply a known load over a course of time, and check voltage readings at regular timed intervals. A very simplified version of how we've done it in Telecoms for years (y)

    For the load, you can just use the motorhome - turn a stuff on, and monitor the battery voltage(s)
     
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  6. Derbyshire wanderer

    Derbyshire wanderer Funster Life Member

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    If you can borrow one, use a CTEK charger on the recondition setting. It will desulphate the batteries (one at a time).
    I do mine once every 6 months and can tell the difference once done. Worth a try and if it works it is worth thinking about buying one. I was sceptical about spending £100+ on a charger but not regretted it.
     
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  7. bubble63

    bubble63 Funster

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    Nice try but most batteries are sealed and already have the little window that shows green when charged

    drop testers arn't that expensive!


    £22 + post
     
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