Battery voltage drop under load.

Discussion in 'Motorhome Chat' started by gazza280, Mar 20, 2014.

  1. gazza280

    gazza280 Read Only Funster

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    Hi Guys

    Just a quick bit of advice please.

    I have been using my new leisure batteries for the first time off hook up they have been fully charged by my new solar panel.
    Under load, that includes new television and aerial booster, eberspacher heater and a laptop, the small plug in meter, says that the batteries have a voltage of between 11.5v and 11.8 and when no load jumps back up to 12.8v 13v.

    My query is this.
    I know that under load the voltage will go below 12v but how far below. Is it normal for the voltage to go lower than 11.5v. If when no load is applied it jumps back to 12.6v / 13v.

    I know that if the voltage stays below 11.2v with not load it must be charged before becoming damaged

    Previously when using a single leisure battery the voltage has only fallen to 11.8v hence the question.

    Many thanks Guys
     
    Last edited: Mar 20, 2014
  2. aba

    aba

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    sounds like either a bad battery cell or bad connection
     
  3. pappajohn

    pappajohn Funster Life Member

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    check the voltage with a proper, handheld multimeter, dont rely on the control panel to give an accurate voltage.

    Not unusual for a lead acid battery to show a low voltage under load but that does appear extreme for such a light loading.
    An engine battery will drop down to around 9v when cranking but soon comes back to 12.6v without the engine running....although that is drawing 300 or 400 amps

    As an aside.......12v, off load, is considered flat.....11.2v is more than likely terminal and the damage is already being done....battery calcification has already begun.
     
    Last edited: Mar 20, 2014
  4. Wildman

    Wildman Read Only Funster

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    Are you testing it in the night when the solar is not charging? Otherwise you will find the meter is reading the solar voltage rather than the actual battery voltage. You do list quite a number of items with no mention of how many watts they consume. If you let us know the total wattage or even the number of amps being consumed a more accurate answer may emerge.
     
  5. PhilandMena

    PhilandMena Funster

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