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What if I run out of battery while in sleep mode?

D

doxavita

macrumors 6502a
Original poster
Jul 6, 2010
614
3
I have a 13" 2010 MacBook Pro running Snow Leopard.

When I close the display and it enters sleep mode it drains aprox. 1% of battery per hour...:

a. What if it reaches 0% while still in sleep?
b. Can that event damage my macbook pro? & it's files?
c. Is it best to always wake it up shortly beforehand and charge again?
d. Do I have to hold the power button to turn it on again (after battery is completely drainned?)

Thanks
 
i leave my macbook in sleep over night and it drains it about 4-5% OVER NIGHT

if it does run out of battery, ur computer simply turns off until you plug it back in

LOL
 
At about 5% battery life the machine will hibernate/safe sleep. This is when the ram contents are put on to the hard drive and then the machine is powered down. However, by default on Intell based Mac laptops, the machine always hibernates/safe sleeps and sleeps. So that the battery can be removed without causing harm.
 
If the battery dies, you'll see a different screen (almost like it is booting up) as it transfers all the data from the hard drive back into RAM (safe sleep).

If the battery dies, it won't damage anything - the only thing that is active is RAM.
 
If you have Hibernate on (By default, it's on) it saves the RAM to the hard drive everytime you close the lid or go to sleep.

If you have Hibernate off (which I recommend if you have an SSD, to save space) then it will literally "crash". Nothing happens, but I try to keep my battery full before the battery is fully depleted.
 
So by the time it reaches 0%, the system will make sure everything is safe?, and then I guess I would have to charge it again a little bit? about how much? And when I open the display again, I'll see a different screen than usual?

Keep in mind this is while my macbook pro is sleeping, not when I'm using it...
 
Last edited:
I always leave mine charging overnight, just do everything can function properly when it wakes up again :) but it really depends if you can do this or not, and whether power saver mode will affect the MacBook pro in sleep or not I don't know.
 
doxavita said:
I have a 13" 2010 MacBook Pro running Snow Leopard.

When I close the display and it enters sleep mode it drains aprox. 1% of battery per hour...:

a. What if it reaches 0% while still in sleep?
b. Can that event damage my macbook pro? & it's files?
c. Is it best to always wake it up shortly beforehand and charge again?
d. Do I have to hold the power button to turn it on again (after battery is completely drainned?)

Thanks
Click to expand...
a. It'll simply shut down
b. No.
c. Don't bother, your computer knows how to take care of itself.
d. I don't remember, but off the bat I'd say it turns itself back on when it has enough power, don't quote me on that.
 
About how much percentage & for how long should I recharge it before I attempt to turn it on again?
 
When the Macbook is hibernating, you have to press the power button to awaken it. Opening the screen will not do it. But, if you plug it in, it will wake up. Even if the screen is closed. With the screen closed though, it'll go to sleep after loading the contents back into the RAM.
 
doxavita said:
About how much percentage & for how long should I recharge it before I attempt to turn it on again?
Click to expand...

It may take what... a minute? Perhaps two?

Experiment, give it a try and report back, you won't break anything.
 
doxavita said:
So by the time it reaches 0%, the system will make sure everything is safe?, and then I guess I would have to charge it again a little bit? about how much? And when I open the display again, I'll see a different screen than usual?

Keep in mind this is while my macbook pro is sleeping, not when I'm using it...
Click to expand...

It will go to hibernation mode, ie, all power to RAM, hard drive, etc will turn off and the front light will stop fading.

When you plug in your power, it will come back to a full state and restore everything, the way you had it before. You will see a small progress bar that shows the restoration from the hard drive to the RAM.

Don't make a big deal out of it, Macs are good at this :)
 
snaky69 said:
It may take what... a minute? Perhaps two?

Experiment, give it a try and report back, you won't break anything.
Click to expand...

I'm not in my MacBook Pro right now :p , but now I know it's safe to let it drain to 0% while in sleep :)

Hibernation I assume is already enabled. Same thing happens as when I calibrate it.
 
Pretty much, you don't have to worry about it.

If it were true that you lose all your files when your battery dies, we would never hear the end of all the complaints because having your battery die is a very common thing.
 
Virtually all modern operating systems & hardware are good at keeping files safe when your computers shut off unexpectedly. Going from hibernation to full awake mode is super safe.
 
doxavita said:
Same thing happens as when I calibrate it.
Click to expand...
You don't need to calibrate your battery. The built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require regular calibration like the removable batteries.

If it shuts off due to battery drain, it may take up to a few minutes of charging before it will power on, but not much more than that. It will not power itself on.

This should answer most, if not all, of your battery questions:
 
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