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The really dumb thing is that, as far as I can tell, a battery's controller generally counts a "cycle" as "started discharging, started charging", regardless of
by mistercow 13y ago
The really dumb thing is that, as far as I can tell, a battery's controller generally counts a "cycle" as "started discharging, started charging", regardless of time in between. At least, that's how it was with my MacBook a few years ago. Unplug, plug in, cycle count increases.
The crappy thing about that is warranties. Apple, for example (at least last I checked; I don't use a Mac anymore) , would replace a battery if it had under some number of charge cycles (and presumably was less than a year old), but not if it had more than that number.
That means that if you treat your battery really nicely by always keeping its charge between 40% and 60%, and it turns out to be defective, they probably won't replace it because of how many "cycles" it has gone through.
Of course, those kinds of cycles have very little to do with the longevity of a Li+ or LiPo battery anyway. A better metric would be total energy output over time, which would be far simpler to calculate anyway.
- hedgehog 13y agoI don't believe that description of cycle count has ever been accurate for Apple hardware and certainly isn't for recent MacBook Airs: http://support.apple.com/kb/HT1519 http://support.apple.com/kb/HT1519
- hobs 13y agoYeah it definitely doesnt, I have had and used dozens of macbooks and you cant ever plug in and out and see your charge cycle increase each time. I usually have my laptops 1-2 years and they rarely go above 300 charge cycles per year, and I usually dc my laptop 5-10 times a day.
- lysol 13y agoIf you read the documentation a cycle is considered a full charge and discharge of the battery. It doesn't have to be discharged or charged fully, but when you've charged the full capacity of the battery and discharged that same amount, that's a cycle.
- mistercow 13y agoSure, but that was not reflected in System Profiler when I actually tested it. Unfortunately I can't test it again now, as my old MacBook's battery will hold up for approximately 14ms before the computer shuts off.
- JimmaDaRustla 13y agoA battery engineer would view that as a cycle, but Apple does not. Funny thing is, I don't imagine any li-on battery lasting 1000 cycles after full discharges! Good warranty or what!?