26650 battery recovery

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Zulumoose's picture
Last seen: 5 min 31 sec ago
Joined: 04/13/2017 - 09:25
Posts: 560
Location: South Africa
26650 battery recovery

So I ordered a pair of these Sunway 26650 5000mAh from the Sunway store on Ali.

They arrived at almost exactly 4V, which is higher than any batteries I have received before.
I immediately tried them in my L2, and they just fit width-wise, seem perfect length-wise with the included magnets between them.
Light worked well so I put them in my Lii500 for a normal discharge cycle test.

End result 4506@4.2v and 4499@4.19V. Took about 15 hours to charge/discharge/charge since the discharge is limited to 500mA.

I thought at first these are 4500 models being sold as 5000, then I thought, maybe they are old, or were stored at too high a voltage, let me try again and see if they improve with another cycle.

End result about 4570 and 4607 (from memory – I forgot to record). I haven’t tried again yet.

Old? badly stored? overrated?
Should I just continue to cycle and see what happens?
I’m not disappointed, just curious about the discrepancy and the reason for it. Other batteries I have received have always been within 5% of rated capacity, and never over 3.8V on arrival. Maybe I’ve just been lucky? What is a reasonable expectation?

Beam me up!

Last seen: 5 hours 40 min ago
Joined: 06/11/2016 - 13:03
Posts: 1158
Location: Bay, St. Louis Mississippi

If they were charged and stored at FL voltage for several months it would lose several hundred mah. I’ve seen it happen in my own cells.

Or the cells could be 4500s rewrapped as 5000

And sometimes cells will increase mah after a few charge discharge cycles. Do the the discharge rest 2 or 3 more times and see if it gets any higher

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snakebite's picture
Last seen: 12 hours 3 min ago
Joined: 11/20/2013 - 20:21
Posts: 1709
Location: dayton oh

run a few cycles to “break them in”
those cells are among the best if not counterfeit.
they usually exceed their ratings sometimes by a large margin.