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Charging AA Li-ion batteries

Discussion in 'Power Electronics' started by vishwasdanthi8, Apr 1, 2019.

  1. vishwasdanthi8

    vishwasdanthi8

    1
    0
    Apr 1, 2019
    Hello,

    I am trying to charge a AA Li-ion battery that is of 1.5V and 2775 mWh. I have hooked a buck-boost converter to a DC supply source. I can regulate the voltage and current (1V to 30V) and a maximum current of 2.5A.

    I am trying to find out the charge time for the Li-ion battery. How do I proceed with the charging of the battery? I need to record data that includes charge time and voltage. and, how do i know when my battery has charged completely?
     
  2. Alec_t

    Alec_t

    2,607
    686
    Jul 7, 2015
    Welcome to EP!
    Charging/discharging lithium batteries is dangerous, possibly causing fire or explosion if not done properly, so is best done using a dedicated commercial charger.
    Have you read this article?
     
  3. BobK

    BobK

    7,575
    1,633
    Jan 5, 2010
    Lithium Ion batteries are not 1.5V, and, as far as I know do not come in AA size.Most likely you are talking about NiMH batteries.

    Bob
     
  4. hevans1944

    hevans1944 Hop - AC8NS

    4,096
    1,944
    Jun 21, 2012
    Your statement doesn't make sense. Firstly, as @BobK pointed out, lithium ion cells are NOT 1.5 V. You may be thinking of alkaline cells, which DO have a typical open-circuit terminal voltage of 1.5 V. Unfortunately, alkaline cells are NOT rechargeable.

    Secondly, you may be thinking that you have nickel metal hydride or NiMH cells, which have a typical open-circuit terminal voltage of 1.2 V. These are rechargeable, and in AA size can have energy ratings up to about 2000 mAh.

    Thirdly, battery charge capacity is typically measured in ampere-hours (Ah) or milli-ampere-hours (mAh) NOT in milli-watt-hours (mWh).

    Fourthly, lithium ion cells come in two varieties: primary and secondary. Primary cells are NOT rechargeable and are by far the most common variety, typically used for things like volatile memory backup power during a mains power outage or long-term storage without power. Secondary lithium-ion cells require special charging and discharging techniques, lest they overheat and explode. It is best to purchase a commercial battery charger, specifically rated to charge your particular lithium ion cell, rather than trying to "roll your own," given the obviously little experience you have.

    If you want to continue this discussion and conversation, please upload a picture of the lithium-ion cell you want to recharge, along with the manufacturer's name, model number, and possibly a datasheet. Someone here might then be able to lead you toward a good solution if one exists.
     
  5. Audioguru

    Audioguru

    2,481
    550
    Sep 24, 2016
    Amazon sells Chinese AA size Li-Ion 1.5V battery cells that even have a 5V USB charging jack!
     

    Attached Files:

  6. hevans1944

    hevans1944 Hop - AC8NS

    4,096
    1,944
    Jun 21, 2012
    I think these contain regular 3.7 V Li-ion cells and a buck-converter to reduce the voltage to 1.5 V. Charging from a 5 V USB port would still require some sort of charge-regulating hardware and/or software. And they are a little pricey compared to 1.2 V NiMH cells, but they surely look to be convenient.
     
  7. hevans1944

    hevans1944 Hop - AC8NS

    4,096
    1,944
    Jun 21, 2012
    Oops! It appears both ratings, mWh and mAh, are used to specify battery capacity. My bad. However, the two measurements DO NOT measure the same thing, so you cannot directly compare a mWh rating with a mAh rating. Google "mWh vs mAh" for more information.
     
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