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Minimum amount of power need to charge a li-ion battery

  1. Dec 10, 2012 #1
    What is the minimum amount of power needed to charge a small lithium ion battery of 3.4 V and 2100 mAh?
  2. jcsd
  3. Dec 11, 2012 #2
    A li-ion battery requires a special charging cycle!!

    It is DANGEROUS to just connect it to a power supply!

    Look at the site http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries if you wanna learn more.

    Most li-ion chargers have specialized charging circuits that take care of security, overvoltage, short circuits and such.

    Be VERY careful with li-ion, they explode, they burn, they are not toys.
  4. Dec 11, 2012 #3
    Thanks for the reply. I mean what is the minimum amount of current that can be used to charge a small li-ion battery?
  5. Dec 12, 2012 #4
    I would recommend you read through the link I sent. It specifies a charge current of 1 amp in the beginning. When the battery reaches its voltage the current is decreased until you see a special drop in the voltage across the battery.

    But read from the link and learn. Those guys know what they are talking about :)
  6. Dec 12, 2012 #5
    You don't have to charge with 1A or whatever. I also doubt the 'constant-current' phase of the charge cycle really has to be constant. The point, as I see it, is to charge the cell with a current source (whatever it may be) until it reaches its float voltage at which point any further increase in voltage might – and eventually will – damage the cell. I can't see why there would be an inherent lower limit on the charge current.
  7. Dec 12, 2012 #6
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