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  1. #1
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    Battery cutoff voltage vs 0% battery voltage

    i have a battery which has:
    maximum voltage : 4.35V
    cut-off discharge voltage: 3V

    i want to know what is the voltage which my product should be in 0% battery. is it 3V? Are we supposed to discharge until 3V or we should shutdown the embedded system at higher voltage, e.g. 3.3V? what is the norm for battery operated embedded system? what do they do in mobile phone design?

    BR
    pragash

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    Re: Battery cutoff voltage vs 0% battery voltage

    Hi,

    it (solely) depends on the battery.
    Read the battery datasheet or contact the manufacturer.

    Also visit www.batteryuniversity.com

    Klaus
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    Re: Battery cutoff voltage vs 0% battery voltage

    hi Klaus,
    thank you for the link. i have never seen it before. i reading it right now.

    apart from that, i would like to get some advice from your experience/embedded system design practice.



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    Re: Battery cutoff voltage vs 0% battery voltage

    One thing to consider is whether your device does something bad in the event that supply voltage drops to 3V? Example, loss of data in memory?

    Do you want an alert to appear so you can do one more thing in the last few seconds before things go dark?

    Do you plan to install a protection diode somewhere in case of reverse polarity? A silicon diode subtracts 0.6 volts.


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    Re: Battery cutoff voltage vs 0% battery voltage

    Hi,

    i would like to get some advice from your experience/embedded system design practice
    What advice do you expect?

    Cutoff voltage depends on battery, not on application.
    For sure you may measure the battery voltage...but it gives not much information about health and charge status.
    For better battery information you could use dedicated battery supervisory circuits, like charge counters.

    Klaus
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    Re: Battery cutoff voltage vs 0% battery voltage

    if its a lithium battery then it may well have a circuit in it which stops you from being able to discharge it further down than 3v.
    If not then you should put one such circuit in there.
    But yes, dont go all the way down to 3v (or whatever is the cut-off)...go to 3.3v like you say.

    With lithiums, if their voltage gets too low, they often cant be recharged safely....and you just have to recycle them.

    ANd recharge ther battery back up again.



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    Re: Battery cutoff voltage vs 0% battery voltage

    Quote Originally Posted by KlausST View Post
    Hi,


    What advice do you expect?

    Cutoff voltage depends on battery, not on application.
    For sure you may measure the battery voltage...but it gives not much information about health and charge status.
    For better battery information you could use dedicated battery supervisory circuits, like charge counters.

    Klaus
    what u mean by depends on the battery? battery type/chemistry? we are using lithium polymer battery.



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    Re: Battery cutoff voltage vs 0% battery voltage

    Hi,

    what u mean by depends on the battery? battery type/chemistry? we are using lithium polymer battery
    Battey type --> yes
    Chemistry --> yes
    In detail also on: Manufacturer, operating temperature, expected lifetime, load current ...

    Thus the only reliable way is"
    Read the battery datasheet or contact the manufacturer.
    Every thing else is "guessing" and will result in "trial and failure".

    Klaus
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