Battery state of charge

Discussion in 'Tech/Mech General' started by Mike B, Sep 3, 2014.

  1. Mike B

    Mike B Funster

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    Measuring the charge in your leisure battery

    To enable you to do this, you will need a digital multimeter. These are not expensive and small simple multimeters can usually be found for around £10 in electronic shops or big DIY stores. Set the multimeter scale to read 20 volts DC. With the 12 volt electrical system turned off, place the red lead on the positive terminal (+ve) and the black lead on the negative terminal (-ve). Read the voltage displayed on the multimeter. To maximise the life of the battery, it is advised you never let the charge drop below 50%.

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    Charge Levels for a lead acid battery

    Leisure batteries with a voltage of below 11.81 should only be charged with a 4 stage charger otherwise damage to the plates may occur. For the best charging performance when the leisure battery is not in use (over winter) look for a charger that offers a 4 stage charging process ( Bulk – Absorption – Equalisation – Float).

    For the most accurate results using this method of measuring the state of charge (SOC) the battery should have been rested for at least 6 hours – i.e not been charged or any load put on it.

    Other factors also determine the SOC, like temperature for example. This is offered as a guide ONLY.
     
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  2. Wildbill

    Wildbill Funster

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  3. Wissel

    Wissel Read Only Funster

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    That depends on whether your batteries have had any form of charging (EHU, driving, solar) during the last 6 hours (some tests state 24 hours to get an accurate reading).

    A completely ruined battery will show 13v if a charger is or has recently been connected.

    If your battery is showing 12.9v after having nothing connected to it for 6 hours then yes, it's good :)

    (don't you just love 12v electrics)
     
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  4. Wildbill

    Wildbill Funster

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    I disconnected the soler to find out if there was any power drain two days ago and there holding at 12.82
    so that's good I think
     
  5. andy63

    andy63 Funster

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    handy table, and I did ask a question in a thread a while ago about whether most people were happy to determine the state of charge of their battery simply by checking the voltage or by using a power management panel showing amp hrs used..... it got lost in the thread and not answered:)

    there are so many variables in every ones circumstances..
    and there is the discharge rate of the battery to consider ie 100ah battery at a given 20 hrs indicates the information relates to a 5ah discharge rate and if you exceed this then the battery will last correspondingly less time than expected.... the 50% rule already mentioned etc etc...
    I came to the conclusion that yes you have to do a bit of research about your power requirements and match it as best you can to your supply source/sources , but most importantly use your van and get to know your own circumstances ..
    I decided the best way for me to keep an eye on my usage was to fit a power management panel..

    ta andy
     
  6. Don Quixote

    Don Quixote Funster

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