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Time to Replace Battery

M

ManhattanPrjct

macrumors 6502
Original poster
Oct 6, 2008
354
1
I routinely put my Macbook to sleep with a full-charge at night, then unplug it (the power cord doesn't reach where I keep my computer at night). When I wake it up, it generally has 93% of a charge left. This has never happened and I am wondering if it is time to replace the battery.

Has this happened to everyone?
 
Calibrate your battery first. Your MacBook will stop charging at ~94%, but if I understand correctly, you're not charging it at night? It's wasting 7% for a ~12h sleep?
 
How old is it? How many cycles are on it?

These are more important than a one-time occurrence like that. It may be that it woke up that night to run monthly scripts or something.
 
download coconutbattery and see what health percentage it gives you.
If it's close to 100% you prolly don't need to spend the money on a new battery.

And depending on how many hours you sleep, it's not abnormal for the MB to use up about 1% battery for every hours it stays asleep.
 
according to coconut battery, it says i have gone through 106 cycles and both meters are at 99%. i guess i need a calibration.

just for my reference - how many cycles are these batteries good for?
 
ManhattanPrjct said:
just for my reference - how many cycles are these batteries good for?
Click to expand...

300 Cycles is the pretty much the current threshold; many people will get a lot more than that; the newer batteries such as the ones in the 17" MBP are rated for up to 1000 cycles.
 
VSMacOne said:
0-100%, regardless of whether it's in increments or all together.
Click to expand...

Are you sure? Or maybe I'm just misunderstanding what you're saying. I thought it was something like once it gets down below 70% or something, when you charge it back up, that constitutes a cycle.
 
My Macbook battery is nearing 300 cycles, 97% health and I bought it December 2006.

Only when it gets to about 60% health you might need to change it because they don't last for long at that state
 
bozz2006 said:
Are you sure? Or maybe I'm just misunderstanding what you're saying. I thought it was something like once it gets down below 70% or something, when you charge it back up, that constitutes a cycle.
Click to expand...

As a safeguard, the battery will not recharge if it's above 95%. Anything below that, counts as charging, thus the battery keeps track of the percentage. Any time you charge your battery, whether it's 5% or 30%, it all adds up to 100% and that counts as a cycle.
 
I'm still not clear on what you're saying, when you mention increments and when you say it all adds up to 100%. do you mean, for example, that if you unplug the computer, then use it on battery until it goes down to 80%, then plug it back in, it won't count as a cycle until you've done this 5 (20% + 20% + 20% + 20% + 20% = 100%)times. I'm pretty sure that's not correct.
 
bozz2006 said:
I'm still not clear on what you're saying, when you mention increments and when you say it all adds up to 100%. do you mean, for example, that if you unplug the computer, then use it on battery until it goes down to 80%, then plug it back in, it won't count as a cycle until you've done this 5 (20% + 20% + 20% + 20% + 20% = 100%)times. I'm pretty sure that's not correct.
Click to expand...
That is correct.

http://support.apple.com/kb/HT1519

A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could use your notebook for an hour or more one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle.
Click to expand...
 
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