View Full Version : Battery only charges to 99%?

Jan 7, 2011, 01:39 PM
I've had my 11" ultimate for about 3 weeks. Its mostly used by the wife around the house so I never really noticed before that the battery never charges to 100%.

I'll leave it plugged in overnight. Open it up and it tells me it charged, however as soon as I unplug the cord it reads 99%.

Does anyone ever see 100%? I know it really has no bearing on battery life, which is great on this machine, but all my previous laptops have said 100% when fully charged?

Jan 7, 2011, 01:42 PM

It is also normal that your battery may not charge to 100%. The battery may appear to stop charging between 93 percent and 99 percent, because the batteries are designed to avoid short discharge/charge cycles in order to prolong the overall life of the battery. When it reaches a full charge, the light on your MagSafe adapter will turn green. This indicates that it has stopped charging your battery and you are now running on A/C power with a fully charged battery. It will not overcharge your battery. It's also perfectly safe to let your Mac notebook sleep with A/C plugged in.
Apple Portables: Battery may not show a full charge in Mac OS X (http://support.apple.com/kb/TS1909)
If you have problems with charging, this might help:
Apple Portables: Troubleshooting MagSafe adapters (http://support.apple.com/kb/ts1713)
Intel-based Macs: Resetting the System Management Controller (SMC) (http://support.apple.com/kb/ht3964)


Jan 7, 2011, 02:24 PM
Also one small note, there's really no point to get obsessed with this "100% charge". In fact, for a Li-ion type of battery, the battery will last the longest if it's always used within 30-70% range. When it stays completely drained or maximum charged over a period of time, it's when the battery gets damaged the most.

Jan 7, 2011, 04:30 PM

See even after calibration I still don't see 100%. But again, not the end of the world for me. Still love the machine.