Calibrating battery lowered its capacity by 4%

[benthewraith]

So I decided to calibrate my battery last night, something Apple told me to do and something everyone recommended. And for the most part, on my old laptop, when I calibrated it, it got longer life. Now, CoconutBattery before the calibration said I had 94% on current battery capacity, but this morning (morning after the calibration) it said I had 90% Battery capacity. The calibrating made it worse.

Did I mess up on something? Please help.

 

[Moe]

So I decided to calibrate my battery last night, something Apple told me to do and something everyone recommended. And for the most part, on my old laptop, when I calibrated it, it got longer life. Now, CoconutBattery before the calibration said I had 94% on current battery capacity, but this morning (morning after the calibration) it said I had 90% Battery capacity. The calibrating made it worse.

Did I mess up on something? Please help.

Did you let it sit on the charger for two hours after it reached full charge? Did you let it run down to the point where it put itself to sleep because of low power and then let it sit 5 hours (or enough to cause it to terminate sleep and shut down for a couple of hours)?

 

[Makosuke]

This is totally normal, and in fact it's one of the reasons you calibrate. The suggestions made might explain why the capacity went down, but more likely it's just lost some capacity over time--that happens--but the battery's computer hadn't realized it yet.

So what really happened is that the battery now knows how much capacity it has, instead of thinking it has more than it does. That can cause sudden forced sleeps when you think you still have power left, or the battery to suddenly appear to lose a bunch of time remaining (all that is really happening in those situations is that it suddenly realizes it didn't have as much power as it thought it did).

I have, for example, seen mistreated batteries that clearly didn't have anywhere near the capacity they thought they did--the battery would go from 50% to basically zero in one jump. Calibrating significantly reduced the reported available capacity, but it also meant that the meter in the menu correctly reported how much time/charge was left, instead of being totally wrong.

 

[archurban]

the beast way to use battery is when it left little over 20%, you should recharge. usually complete discharge is not good for battery life. plus, calibration is helpful. but it is wasted product. someday you will replace by new one. so don't worry about it too much. when your battery goes 5 hours, it's fine.

 

[benthewraith]

I did let it sit for two hours before removing it from the charger. I then depleted the charge forcing it to sleep. I right about then put it back on the charger and went to bed. Which is according to Apple's site, incorrect. After another charge cycle, it went back from 90% to 94% battery capacity. I didn't let it sit for five hours nor did I turn it off before calibrating.