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Old 12-05-2012, 11:24 AM   #17
Mono
Mono
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Posts: 699
Karma: 13333
Join Date: Jan 2012
Device: Boox M92
Quote:
Originally Posted by dkef View Post
And no, my experience is that lithium batteries do not degrade significantly after a couple of years of inactivity. It might not be charged, but after a couple of charges it should be OK.
Quote from Wiki:
"A Standard (Cobalt) Li-ion cell that is full most of the time at 25 C (77 F) irreversibly loses approximately 20% capacity per year. Poor ventilation may increase temperatures, further shortening battery life. Loss rates vary by temperature: 6% loss at 0 C (32 F), 20% at 25 C (77 F), and 35% at 40 C (104 F). When stored at 40%–60% charge level, the capacity loss is reduced to 2%, 4%, and 15%, respectively. In contrast, the calendar life of LiFePO4 cells is not affected by being kept at a high state of charge."
http://en.wikipedia.org/wiki/Lithium-ion_battery

So, it battery is full and is stored at room temperature, it has no capacity in 5 years, even if not used. To keep it in good health possibly requires it to store it half-charged and in refrigerator.

But, there is not only one type of Li-ion battery, but about 5+. The citation holds for standard one....

M92 is not comparable to cell-phone. Modern cell phone has to be charged every 1-5 days (depending if smart or not). M92 say every 2 weeks... Depends if WiFi is used... So it may be 25 charging cycles per year comparing to 360 cycles/yr for smarphone.

Last edited by Mono; 12-05-2012 at 11:26 AM.
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