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Questions lithium polymer battery

Discussion in 'Power Electronics' started by gamer87, Jan 10, 2020.

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  1. gamer87

    gamer87

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    Mar 11, 2017
    What type long term storage lithium polymer battery?
     
  2. Audioguru

    Audioguru

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    Sep 24, 2016
    Any "ordinary" Lithium Ion or Li-PO battery will last a long time if it is stored at half-charge (3.7V to 3.8V) and is not charged and discharged more than about 500 times.
     
  3. gamer87

    gamer87

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    Mar 11, 2017
    For maximum battery life is only 50% required? Does store in below 50 or above 50% decrease battery life?


    If I recharge a 100% Li-PO battery is it correct to recharge after 3 months? in the manual says to recharge in 3 months
     
  4. Audioguru

    Audioguru

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    Sep 24, 2016
    Lookup battery details at www.batteryuniversity.com .
    If a Lithium battery is fully charged all the time it will not last long. If the battery is discharged below about 3.2V then it will not last long. If it is discharged below about 2.5V then it is permanently ruined.

    They say to charge it every 3 months maybe because it powers something that is running all the time like a clock, or because they wan't to sell you a new battery soon..
     
  5. gamer87

    gamer87

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    Mar 11, 2017
    What percentage of the battery can I recharge without damaging its life? between 50 and 90%?

    the equipment is a plasma pen and they say to charge every 3 months but I don’t know if it will charge up to 100%, plasma pen doesn’t use a clock and doesn’t power anything when it’s turned off
     
  6. bertus

    bertus Moderator

    545
    179
    Nov 8, 2019
    Hello,

    From the give page in post # 16:

    Most Li-ions charge to 4.20V/cell, and every reduction in peak charge voltage of 0.10V/cell is said to double the cycle life. For example, a lithium-ion cell charged to 4.20V/cell typically delivers 300–500 cycles. If charged to only 4.10V/cell, the life can be prolonged to 600–1,000 cycles; 4.0V/cell should deliver 1,200–2,000 and 3.90V/cell should provide 2,400–4,000 cycles.

    On the negative side, a lower peak charge voltage reduces the capacity the battery stores. As a simple guideline, every 70mV reduction in charge voltage lowers the overall capacity by 10 percent. Applying the peak charge voltage on a subsequent charge will restore the full capacity.

    In terms of longevity, the optimal charge voltage is 3.92V/cell. Battery experts believe that this threshold eliminates all voltage-related stresses; going lower may not gain further benefits but induce other symptoms. (See BU-808b: What causes Li-ion to die?) Table 4 summarizes the capacity as a function of charge levels. (All values are estimated; Energy Cells with higher voltage thresholds may deviate.)

    Bertus
     
  7. gamer87

    gamer87

    204
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    Mar 11, 2017
    In the manual of my equipment plasma pen, do you recommend recharging to 100% within 3 months? Is this a good recommendation for maximum long life of the lithium polymer battery?
     
  8. Bluejets

    Bluejets

    3,991
    824
    Oct 5, 2014
    I'd be giving the lipo a swerve and chuck in a sealed lead acid with a converter if you need a different voltage from the standard pd.
    These things have been reliable in alarm systems for donkey's years.
     
  9. dave9

    dave9

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    217
    Mar 5, 2017
    This seems strange to me, what phones used Li-Ion 22 years ago? IIRC most were NiMH at the time.

    Overall this topic looks like another one of those OCD, how-can-I-make-everything-last-forever, misadventures. Consumer access to a wide variety of Li-Ion pack sizes is much better on the internet today, so the question becomes how much work to put into storage, checking voltage, monitoring and prematurely terminating charge voltage, over and over for years, to save from buying a replacement battery when we're talking about % changes here so you may end up buying a replacement battery anyway because nothing lasts forever, AND given enough time, there may be a newer better version of the widget you're trying to make last forever.
     
    Last edited: Jan 18, 2020
  10. gamer87

    gamer87

    204
    0
    Mar 11, 2017
    In the manual of my equipment plasma pen, do you recommend recharging to 100% within 3 months? Is this a good recommendation for maximum long life of the lithium polymer battery?
     
  11. dave9

    dave9

    882
    217
    Mar 5, 2017
    ^ No, never charge it to 100% except to USE it enough that it drops to under 70% at the point of storage again, which may mean don't charge it to 100% at all if your use doesn't drain it that much.

    Charge to closer to 40% to 70% (lower giving longer total lifespan) for storage and yet, this means you must check the storage voltage that much more often because the less total charge it has, the sooner it self discharges too low. If you want to be further obsessive, also store it near freezing. Seal it in an air tight bag and stick in the colder section of your refrigerator, though Li-Ion freezing point is well below the low temperature achieved by a typical consumer freezer too. If you store them that cold, leave them in a sealed container with minimal air in it (plastic baggie evacuated of most excess air) so it doesn't get condensation while it warms up near room temperature before use.

    WHY are you asking here? This info is out there and easy to find with a web search.
     
    Last edited: Jan 18, 2020
  12. gamer87

    gamer87

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    Mar 11, 2017
    The lithium polymer battery of the plasma pen I checked and has an output power of 5V / 1A 5W

    I bought the device, but it hasn't arrived at my house yet, but I'm going to use it and store it and I think it will be delivered with a 100% full battery

    In the manual it says to recharge at once in 3 months but it doesn't say to charge to 100%
     
  13. Audioguru

    Audioguru

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    633
    Sep 24, 2016
    A lithium polymer battery cell is 4.20V when fully charged. A new version is called Graphene and its fully charged voltage is a little higher.

    Your 5V/1A 5W is not the battery, instead it is the output from the power supply that heeds the charger circuit for the battery.
    Or maybe you have a "power bank" that is charged from 5V and it has a voltage boosting circuit that produces a 5V output.
     
  14. gamer87

    gamer87

    204
    0
    Mar 11, 2017
    I don't have precise technical information about the lithium polymer battery of this device. The only conservation information in the manual is to recharge the device every 3 months but it does not say if it is to recharge to 100%
     
  15. Audioguru

    Audioguru

    2,791
    633
    Sep 24, 2016
    I suspect that the battery is an old Ni-Cad and is not Lithium. An old Ni-Cad needed to be recharged often.
     
  16. Alec_t

    Alec_t

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    742
    Jul 7, 2015
    Dave has given you the answer in post #31.
     
  17. gamer87

    gamer87

    204
    0
    Mar 11, 2017
    If I recharge up to 90-95% every 3 months is it correct?
     
  18. Audioguru

    Audioguru

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    633
    Sep 24, 2016
    How do you measure the percentage of charge? It is not its voltage.
    It charges to 4.20V up to 70% of a full charge then it keeps charging as its charging current drops. When its charging current is about 3% of its mAh rating then it is fully charged.
     
  19. gamer87

    gamer87

    204
    0
    Mar 11, 2017
    my equipment's battery meter is measured in bars 4 bars
     
  20. Audioguru

    Audioguru

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    633
    Sep 24, 2016
    Maybe it is the battery meter that is slowly draining the battery all the time.
     
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