Current science on rechargeable battery degradation

ronorboris on 10/12/2014 - 23:33

Like a lot of us, I recently hopped on this deal for Xiaomi portable power banks: https://www.ozbargain.com.au/node/174006

What I'm clueless about though, is what rate these devices lose their capacity/ability to hold a charge and under what circumstances. I've heard/read a lot of disparate information:

  • Rechargeable batteries used to lose their capacity over time, but not any more
  • Li-on batteries lose their charge, but Ni-MH batteries don't (or vice-versa)
  • Leaving batteries on the shelf at all/at 0%/at 100% is bad for them
  • Constantly charging batteries at 100% is bad for them
  • Putting batteries in the fridge/freezer slows their drain, either on the shelf or when in use
  • The ratio of OzBargainers to Eneloops they've bought is 1:8000

I know how to use Google, but this is one of those situations where more information is less.

The 16000mAh Xiaomi power bank has: 5 x LGABE11865 - 3200mAh @ 4.35V (li-on)
The 10400mAh Xiaomi power bank has: 4 x LGABB41865 - 2600mAh @ 3.7V (li-on)

I'm mainly going to be using the 16000mAh device. If I give it several cycles, then charge it to 100% and leave it on the shelf for 6 months, how much degradation should I expect?

Electrical & Electronics

Comments

  • Davo1111 on 11/12/2014 - 00:20
    +2

    Have a look at battery university for tips about storage etc.

    This graph is good for understanding failure rates of rechargable batteries (in this case eneloops)

    http://www.candlepowerforums.com/vb/showthread.php?392229-Ja…

    • ronorboris on 11/12/2014 - 12:50

      Oh man, and here I thought Eneloops were only going to get better :( That was an interesting, if sad, read.

  • ESEMCE on 11/12/2014 - 07:54
    +1

    Lithium are good at holding charge.
    Store them with ~75% in a cool, dry spot.
    Don't store them in the freezer, don't store them in your car on a hot summer's day.
    Try to recharge when they get to 30-40%, try not to run them down to 0% very often.
    When charged, take them off charge as soon as practicable. (although decent charger's will take care of this for you automatically).

    After 6 months, you'll still have 70-80% charge, but it's not ideal storage.. as above, charge to 75% for storage.

    • ronorboris on 11/12/2014 - 13:07

      Oh awesome, so if this has 4 charge level indicator lights I'll just need to do my best to leave it at 3 of 4 lights when not in use. 70%-80% under non-ideal circumstances is not too bad.

      Thanks for the advice! I'll keep it mind when those banks arrive.

  • ty2050 on 14/12/2014 - 22:29

    From what I've read and seen on YouTube. 40% is where you should be storing lithim-ion batteries. Not letting your batteries to 0% will increase battery lifespan. And most important part never use a cheap charger.

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