Are my Batteries Knackered

Discussion in 'Tech/Mech General' started by lunarman, Apr 21, 2010.

  1. lunarman

    lunarman Funster

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    I had a problem over the last weekend. I have 2 110amp leisure batteries that have been on charge all through the winter via EHU, so I assumed that they were fully charged. After 4 hours of television they had dropped to 10v and the tele would not go. The tele only draws 5amp. So I would have expected at least 20hours without problem

    When I got home I took them out and found that each needed about 1.5ltr of water. I have recharged them the charger showed fully charged and 14.2v disconnected from the charger each read 13.8v, now after 24 hours without any load or charge they are reading 12.5v.

    Is it usual for the voltage to drop back so quickly? and are they likely to need replacing.

    Cheers

    Lunarman
     
  2. Dodgey

    Dodgey Funster

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    Don't know the techy stuff, but prolonged hook as I understand it wont do them any good whatsoever and dropping to 12.5, me thinks new batteries time.
     
  3. hilldweller

    hilldweller Funster Life Member

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    Voltage is near enough normal. You're in with a chance, just do your TV load test on them and see how they perform.
     
  4. pappajohn

    pappajohn Funster Life Member

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    They should be 13.8v just off charge.

    12.6v after an hour or two off charge or after applying a light load (21w bulb etc) for a few minutes.

    yours appear to have been constantly charged at 14.2v which is far too high for a maintainance charge and thats why they boiled and needed topping up.

    to leave them on charge indefinately you need a 3 or 4 stage smart charger which will float charge at 13.6v once they are fully charged.

    0.6v doesnt sound much but it makes a great difference to a battery.

    sounds as though your charger is at fault.
     
  5. Madmike

    Madmike Read Only Funster

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    Seem's to me you have two problems.:Eek!::Eek!:
    1 Batteries do not being boiled dry. A fully charged battery should have a charge without load of 12.7 and should be able to maintain that for at least one week.
    2 Batteries only gas/boil if the charger is putting out too much power. I should check that the charger is functioning correctly before even comtemplating new batteries
    Regards,
    Mike
     
  6. DESCO

    DESCO Read Only Funster

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    Hi

    This is the reason I don't leave mine on perm. hook up but on 7 day timer and charge for about 4 hours once a week.

    I have a supply to heater separate for cold weather.


    Dave :thumb::thumb:
     
  7. nomad

    nomad Funster

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    Hi Lunarman, try running the tv and if the voltage drops again disconnect them and do a voltage check on each one independantly as it could be that only one of them is faulty.
    Best of luck
    Colin
     
  8. wireman

    wireman Read Only Funster

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    just off charge you will get up to 13.6 volts

    But the figures that count are (for a battery with no load)

    12.7v is fully chargered
    12.5 is three quarters
    12.4 is half
    12.3 a quarter and anything below would indicate that the battery is effectively flat.
     
  9. lunarman

    lunarman Funster

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    Thanks to all of you who replied.

    The results of the load test carried out over the weekend are:

    09:00 batteries fully charged showing 12.5v switched on tele current drain checked to be 4.7amp

    16:00 switched tele off checked battery voltage to be 11.96v

    total drain 7hrs @ 4.7 = 32.9amphr

    switched tele back on and checked after further 4 hours tele had switched itself off due to low voltage, battery checked showed 9.9v. After a further 24hrs without load battery shows 11.9v

    So the maximum that would have been drawn is 11 hrs @ 4.7 amp = 51.7 amp hours. This from 2x110 amp batteries would indicate to me that they are indeed knackered and I am going to have to replace them. :swear:

    Please tell me I am wrong

    If I am right do I replace with 2x110 or get 2x85 to match up with a spare 85 I have and so end up with a bank of 3 85amphr batteries. Given that the one I have I don't know the date of is this a good idea?
     
    Last edited: Apr 26, 2010
  10. DESCO

    DESCO Read Only Funster

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    Personally I prefer to have batteries matching size, age , type but some seem to get away with it OK.

    But I know my luck I would have problems.

    Dave :thumb::thumb:
     
  11. hilldweller

    hilldweller Funster Life Member

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    You are wrong.





    He lied.

    Here, clutch this straw.....
    All you can do now is repeat the test on each battery in turn just in cast one is dragging the tother down.
     
  12. nicholsong

    nicholsong Read Only Funster

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    Wireman, Hi

    I am not challenging your figures on % 0f charge - very similar to well-known expert in another place.

    Since 0.1 or 0.2 is difference between Full and 3/4, and I get a difference of 0.1 between my static voltmeter and my multimeter volt reading direct into the terminals, which should any of us believe?

    Also I have been told by two battery suppliers that 'drop testers' cannot be used because os safety requirements. Does anybody know if this is correct or are the conpanies just saving money on training. Surely battery manufacturers and the the safety regulators must still use them - so?

    Any Answers Please

    Geoff
     
  13. wireman

    wireman Read Only Funster

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    What multimeter is it and I'm assuming a static voltmeter in the van?

    TBH reading 0.2v on a static voltmter (I'm assuming analogue rather than digital) is rather difficult unless you have one that reads from 11 to 13v over a largish scale. Anything else is really just and indicator. A reasonable qual;ity digital multimeter will give you a reasoonably accurate reading, my £15 quid one is accurate enough.

    But don't worry too much, if you charge the battery for 24 hours, let it rest for an hour and measure the voltage it vwill give you a good general idea of the state of the battery.

    Oh and voltage drop accross the cable if the volmeter is a way from the batteries.
     
    Last edited: Apr 26, 2010
  14. lunarman

    lunarman Funster

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    Hi Wireman,

    All the readings were taken with good quality digital multimeter.

    Lunarman
     
  15. wireman

    wireman Read Only Funster

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    if they are only showing 12.5v fully charged then you have a problem. did you test them individually just in casse you have a bad one and a good one....
     
  16. lunarman

    lunarman Funster

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    Taran Las asked what the outcome of this was in another post.

    I charged each battery separately and after 24 hrs off charge one settled to 12.49v the other 12.43v. Testing each with the tele and after 4hrs @ 4.7amp drain they were down to 11v so I presumed that they were indeed knackered and needed to be replaced.

    I decided that as they were in an inaccessible position to get sealed for life maintenance free ones and purchased 2 105amp numax batteries @ £78 each. This will hopefully prevent the problem that I originally had - running dry.

    I am now looking at fitting a solar panel but don't like the £500 price tag!!

    Thanks for all the advice .

    Lunarman
     
  17. hilldweller

    hilldweller Funster Life Member

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    Not so sure about that. If whatever charges them is cooking them then sealed will be damaged. Check voltages for a while just in case.

    ebay has a big variation in prices on solar, if you fancy buying something like that off ebay.
     
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