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No. of recharge cycles irrelevant?
Authored by: Winston on Sep 16, '03 11:53:38AM
The number of full charge cycles is relevant. LiIons are supposed to get about 500 full charge discharge cycles. However because of the natural degradation over time, its more likely that aging will kill the battery than use, although use is a factor.
If you constantly charged/discharged the LiIon several times a day you might have a bigger influence from the charge/discharge cycles.
The Apple article is consistent with my post. It says:
The battery appears to stop charging between 95 percent and 99 percent.
This is normal. The batteries used in these computers are designed to avoid short discharge/charge cycles in order to prolong the overall life of the battery. Because of this, when setting the Mac OS X battery status menu bar icon to display charge state by percentage, you may notice that the reported charge stays between 95 percent and 99 percent. When the battery level eventually drops below 95 percent, it will charge all the way to 100 percent.

There are two issues: 1. What the battery monitor says. 2. "short charge/discharge cycles"
1. The battery monitor is only an estimate. If it never gets to 100% it is because the circuit in the battery decided the battery was charged before the battery monitor got to 100%. Apple has instructions for calibrating the battery monitor which basically say charge the computer fully, use it until it goes into forced sleep, then charge it fully again. This resets the computer's battery monitor, but does nothing for the battery
2. The issue is preventing LiIons from overcharging. Once fully charged, they can't be left on "trickle charge" without danger of overcharging. As a result, they have to run down a bit before the battery's charging cycle will let them start being charged again. There may be some issue on very short charges, but the main issue is not overcharging the battery.

- Winston

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