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Remaining battery reading not accurate.

D

doxavita

macrumors 6502a
Original poster
Jul 6, 2010
614
3
The remaining battery indicator (top right) is not completely accurate. The measurement (time) constantly varies.

As far as I know a 13" MacBook Pro should have 10 hours battery time. In this case the reading constantly changes from about 8:52 hours then back to 9:12 hours, 9:34, and other readings, etc.

Is this normal?
 
Calibrate it. Also, the time remaining changes dynamically as your current battery load changes. Some things draw power faster than others.

This should answer most, if not all, of your battery questions: Apple Notebook Battery FAQ
 
Well, yesterday my battery got pretty low (18%), and I fully recharged it.
Don't know if that counts as "calibrating".
If not, I'll follow the exact steps for that.
 
doxavita said:
Well, yesterday my battery got pretty low (18%), and I fully recharged it.
Don't know if that counts as "calibrating".
If not, I'll follow the exact steps for that.
Click to expand...

That's not calibrating. You'll find a link to the proper instructions by following the link I posted.
 
OK, I'll do that. Since calibrating takes many hours, I can do the entire procedure in more than one day, right?
 
yeah, just use it untill you ave no power. close programs and let it go to sleep by itself. Then wait 5 hours (overnight). and then I left it in charge before work. Came back and started using it again. voila
 
I calibrated my MBP when I first got it and followed the instructions GGJstudios. It worked great.

The only thing I did additional was to use the info from this site/video to help drain the battery faster:

http://www.unixweblog.com/2010/05/calibrating-the-battery-on-an-apple-macbook-macbook-pro/

By setting up 4 terminal windows I was able to go from a full battery to completely dead in just over an hour. Just make once the computer shuts off that you leave it for ATLEAST 5 hours. This will finish the discharge of your battery. At that point, just plug it in and leave it.
 
"5. After your computer goes to sleep, turn it off or allow it to sleep for five hours or longer."


1. Does that mean that when it's in sleep, I have to wake it and then shut it down?

2. If I shut it down, how many hours do I have to wait?
 
doxavita said:
"5. After your computer goes to sleep, turn it off or allow it to sleep for five hours or longer."


1. Does that mean that when it's in sleep, I have to wake it and then shut it down?

2. If I shut it down, how many hours do I have to wait?
Click to expand...

Once the battery gets really low you'll get a notification. Keep using the laptop until it shuts off on it's own. At this point, just set it aside for 5 hours. Do not try to power it up again.

After 5 hours, just plug it in and wait a few minutes. Then power up and let it charge to full.
 
NKT said:
Once the battery gets really low you'll get a notification. Keep using the laptop until it shuts off on it's own. At this point, just set it aside for 5 hours. Do not try to power it up again.
Click to expand...

So when it goes to sleep, I can just close the display and leave it like that for at least 5 hours?
 
doxavita said:
"5. After your computer goes to sleep, turn it off or allow it to sleep for five hours or longer."


1. Does that mean that when it's in sleep, I have to wake it and then shut it down?

2. If I shut it down, how many hours do I have to wait?
Click to expand...

No, when the battery gets low enough, it will automatically sleep or power off. Just let it sit like that for 5 hours before you reconnect the charger.
 
Yesterday I fully recharged my battery (until green led in power adapter) and I'm pretty sure 2 hours passed after that.

Following that link you provided me (Apple Notebook Battery FAQ) there's this comment:
"AppleCare support recommends that if you leave your Mac plugged in most of the time, unplug it every 2 or 3 days and run on battery down to somewhere around 50%, then plug it back in. That keeps the electrons moving."

So today instead of waiting until 50% and recharging, I can just wait till 0% and starting doing the battery calibration right away, right?
 
doxavita said:
Yesterday I fully recharged my battery (until green led in power adapter) and I'm pretty sure 2 hours passed after that.

Following that link you provided me (Apple Notebook Battery FAQ) there's this comment:
"AppleCare support recommends that if you leave your Mac plugged in most of the time, unplug it every 2 or 3 days and run on battery down to somewhere around 50%, then plug it back in. That keeps the electrons moving."

So today instead of waiting until 50% and recharging, I can just wait till 0% and starting doing the battery calibration right away, right?
Click to expand...

The calibration steps are very clear. Read the steps and follow them exactly. You can calibrate at any time, but remember that calibration starts by fully charging your battery and leaving it fully charged and plugged in for at least 2 hours.
 
GGJstudios said:
The calibration steps are very clear. Read the steps and follow them exactly. You can calibrate at any time, but remember that calibration starts by fully charging your battery and leaving it fully charged and plugged in for at least 2 hours.
Click to expand...

^
This
 
GGJstudios said:
The calibration steps are very clear. Read the steps and follow them exactly. You can calibrate at any time, but remember that calibration starts by fully charging your battery and leaving it fully charged and plugged in for at least 2 hours.
Click to expand...

Yes, that's what I did yesterday (recharging and waiting 2 hours). So today I'll just do the calibration.
 
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