Over 100,000 cycles on a 18650?

jasonck08

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Came across an article / 10 year lab test of some Sony 18650-HC cells. They did several different types of tests, but one of them, they did over 100,000 cycles @ ~20% DOD. I only briefly looked at the article, but its quite interesting. Seems that if you only discharged to 20% DOD, you could get a LOT of life out of a cell and it could be in service for over 10 years.



http://www.dtic.mil/cgi-bin/GetTRDoc...fAD=ADA515369
 

tandem

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I ran across the same report today and wondered if it had been mentioned so bumping the thread.

www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA515369

These eight cells were initially very well matched in capacity. However, we exposed the cells to anaging process that was designed to introduce an imbalance of 10% between the capacities ofthese
cells. This procedure involved storing these cells at voltages between 3.4 and 4.2 V at ambient temperature
for 220 days. This procedure resulted in nearly a 10% capacity loss in the cells stored at the
highest voltages and very little capacity loss in the cells stored at the lowest potentials.

All kinds of interesting tidbits in the report.
 

ChrisGarrett

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I recently disassembled a Sony VAIO pack that my brother got with his laptop in 2004. The pack has been in my possession (along with 2 others) for at least 3 years and I jacked up the oldest, non-working one, last May and got 8 2000mAh Sonys out of it with date codes of 2002!

I've charged them up at 500mA and never put a heavy load on them, but they held their charge for a couple of months and according to my Convoy lights with 2.8A drivers and a medium of 40%, I'm getting decent capacity out of them.

They charge up to 4.17v and settle at around 4.14v-4.15v, where they've ALL stayed for the 8+ weeks, back then. They're all in the fridge now.

Obviously cycles and calendar lifespan are two different parameters, but coming from somebody who's understanding is/was 3-5 years, used or not, I was surprised.

Chris
 

tandem

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My bet is our single-cell li-ion powered flash lights are probably going to be serviced by their 18650's for a very long time.
 
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