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New phone battery voltage

  1. Jan 16, 2016 #1
    Hi,
    I recently bought a new battery for my phone, and before installing it, checked it's voltage, to be Zero. I understand that there may be protection circuits in the battery, but I assume it should still show a voltage. As it's a Li-on battery the voltage should be between 3.5 and 4.2v. The old battery still shows 4.1v.

    I told the battery supplier, while trying it in the phone. They said to return it, and before I did, it had died. I received a replacement (In sealed pack), and as before no voltage.

    Should there be a voltage on a new phone?

    Camerart.
     
  2. jcsd
  3. Jan 16, 2016 #2

    Bystander

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    Zero voltage? Li batteries can be "flaky."
     
  4. Jan 16, 2016 #3
    Is it possible that the battery internal circuit, could stop it showing voltage till it has been charged? Or should it simply show a voltage between 3.5 and 4.2V out of the packet?

    C.
     
  5. Jan 16, 2016 #4

    CWatters

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    I think most batteries should indicate a voltage. Universal battery chargers use it to work out which pin is +ve and -ve.
     
  6. Jan 16, 2016 #5
    Hi C,
    Fair enough, but this would be in the phone, so no working out.
    C.
     
  7. Jan 16, 2016 #6
    Hi,

    Is there anyone, who deals with or knows how phone batteries work, or anything about phone battery storage mode, if there is one?

    C.
     
  8. Jan 16, 2016 #7

    CWatters

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  9. Jan 16, 2016 #8
    Hi C,
    Thanks, I am aware that Li-on cells should be kept (you say 2V) I think between 3.5 and 4.2 as said previously, but if a cell has a protective circuit, that shuts it off below 'say' 3.5v, then at 3.49 it may show zero volts, and looks dead flat.
    Are you experienced with Phone batteries and their circuits? If so I'll accept your word, and send it back.
    C.
     
  10. Jan 16, 2016 #9

    CWatters

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    I see what you mean about the protection circuit. Afraid I can't be sure. All the phone batteries I've purchased have arrived with enough charge to power up a phone and some.
     
  11. Jan 16, 2016 #10
    My experience is that many batteries bought on-line are probably past their "sell-by" date and the sellers let the customers do the quality control.
    (Printer cartridges, too.)
     
  12. Jan 16, 2016 #11
    Hi,
    This is the fifth battery I've tried, being the second from a supposedly 'good' online supplier, and was not cheap. I have only chcked the voltage before putting them into the phone, on these last two, both having zero voltage. I too suspect that they are old stock, and if my memory serves me well, I can't get them from a shop.

    This last one actually showed a never before pop up on the phone saying can't start the phone, not enough voltage.

    I'll report this again to the supplier, including the 'sell by' bit, and see what they say.

    Thanks, C.
     
  13. Jan 16, 2016 #12

    meBigGuy

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    Lithium cells have a safety circuit designed to stop the battery from discharging below 2.7V. I've never tried to measure the voltage once it discharged below 2.7 to see whether there is enough leakage to get a voltmeter reading. It's possible the meter would read zero.

    In order for the battery to recover from this low state of discharge the phone needs to be connected to the charger. It will enter a Lithium PreCharge phase until the battery reaches a certain level. It will then enter the constant current phase to continue to charge the battery.

    You should try charging the battery in the phone. If it does not accept a charge, or if it does not behave normally after charging (normal battery life) then the battery is faulty.
    If the battery charges, I'd run some sort of test to see how long it takes to fully discharge. That may also help calibrate the internal state of charge (fuel gauge) circuitry in the phone.

    Personally I think it is a bad battery. Lithium shelf life is many years, so you should not see zero volts. Of course, you need to measure across the proper terminals.
    But, I'm just guessing in this respect.
     
  14. Jan 17, 2016 #13
    Hi,

    I think we all concur in our own ways. I looked up storage voltage, and there is a variation from 2-3.8v, also store at room temperature, for best results. I have an electric bike, and try to keep it above 3.5v. Regarding the protection circuit, I have other cells that show zero volts if taken below their circuit voltage, so I assume it's the same for the phone one. Also the circuit, runs down the cell, so they must be monitored and charged if too old.

    I have reported it to the suppliers, as I too think it's suspect, while charging it in the phone as a test. I will get the feel for how it performs. From memory, it's the best option in my case, as I think there may not be many of this type made any more.

    C.
     
  15. Jan 17, 2016 #14
    Hi, (Is there no edit facility?)

    I've just remembered! As mentioned this is the second battery from this supplier, so I'm repeating the above operation, as the first one died after about 3 weeks. They did send this replacement however!

    C.
     
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