Filed under: Hardware, Portables, iBook, PowerBook, PowerMac G5, Macbook Pro, MacBook, MacBook Air
Battery calibration recommended by Apple, why no utility?
Like virtually all mobile computer manufacturers, Apple recommends that users calibrate their laptop batteries every few months, as Scott pointed out a couple of years ago. Unlike many manufacturers, however, Apple does not include a utility to automatically perform a calibration. Given Apple's uncanny ability to make things user-friendly, this seems like a bit of a glaring oversight.
What are the benefits of calibration? Primarily the goal is to ensure that the microprocessor in your battery provides an accurate estimate of how much time you have left on the battery. Over time it can lose track of just how much juice your battery has in it, and calibration gives it a very accurate reading on the battery's health.
Older battery technologies also benefited from a process called conditioning, which was typically performed the same way as a current battery's calibration process. In a nutshell, you fully charge the battery, fully discharge it, then fully charge it again. It's unclear whether modern lithium batteries gain anything in an actual capacity perspective from this process, or if it is simply a calibration of the microprocessor for the purpose of providing accurate time estimates.
Now, if it seems that accurate time estimates are not all that important, consider that you could actually be losing battery time because your laptop is shutting down prematurely. In other words, there might actually be extra juice in your battery that you're not able to use because your laptop thinks the battery is almost depleted when it's not.
So if you'd like to perform a calibration manually on your modern Mac portable*, follow these steps taken from Apple's battery calibration knowledge base article:
- Plug in the power adapter and fully charge your PowerBook's battery until the light ring or LED on the power adapter plug changes to green and the onscreen meter in the menu bar indicates that the battery is fully charged.
- Allow the battery to rest in the fully charged state for at least two hours. You may use your computer during this time as long as the adapter is plugged in.
- Disconnect the power adapter with the computer still on and start running the computer off battery power. You may use your computer during this time. When your battery gets low, you will see the low battery warning dialog on the screen.
- Continue to keep your computer on until it goes to sleep. Save all your work and close all applications when the battery gets very low, before the computer goes to sleep.
- Turn off the computer or allow it to sleep for five hours or more.
- Connect the power adapter and leave it connected until the battery is fully charged again.
If you have an older Mac portable like an iBook or PowerBook G4 other than the PowerBook G4 (15-inch Double-Layer SD), you can skip steps 2, 4, and 5 in the calibration process.
As you can see, while not complicated, battery calibration is a fairly involved process. A utility that walks the user through the process would certainly be useful, and would likely result in a lot more Mac users taking care of their batteries. If you're interested in a tool to check up on the health of your battery, check out TUAW favorite coconutBattery or the venerable iBatt.
* With respect to these instructions, "modern Mac portables" refers to the following: PowerBook G4 (15-inch Double-Layer SD), MacBook (all models), MacBook Pro (all models), and MacBook Pro (17-inch) (all models)
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Reader Comments (Page 1 of 2)
Dah Cheet said 7:42PM on 7-30-2008
I did this when I first got my Air but haven't since. Perhaps I'll do it again some time soon just to see if I can get a better battery health than 97%.
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(01) said 8:04PM on 7-30-2008
I also think it's brutal to need to leave the computer asleep for five hours...as my primary machine, pretty much the only time I don't use my MBP is when I'm asleep...
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CaptSaltyJack said 8:07PM on 7-30-2008
Quick Q about #5: "Turn off the computer or allow it to sleep for five hours or more."
Is that...
Turn off the computer for 5+ hours or let it sleep for 5+ hours, and then plug in the power adapter
OR
Turn off the computer and plug in the power adapter, or let the computer sleep for 5+ hours and then plug in the adapter
Sorry, subtle possible misinterpretations there.. just wanted to be clear.
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Stephen said 9:03PM on 7-30-2008
option A. Don't start recharging until it has rested (either off or asleep) for 5 hours.
Rob said 9:15PM on 7-30-2008
Basically: Let the computer drain down until it automatically goes to sleep.
Then leave it unplugged, sleeping, for 5+ hours.
Then connect power cord and leave plugged in until fully charged....that's it! ;-)
MAR said 8:12PM on 7-30-2008
Note in step #6, I don't believe you can use your computer during this time, unlike step #2. If someone knows otherwise please follow up. I also believe that this process is applicable to the iPhone.
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jerome said 10:00PM on 7-30-2008
ive had my macbook pro for only a little over a year and 2 days go my battery was at 7% health (and has been that way for the past few months). i let it drain down completely until the computer completely shut off. after reconnecting the charger, it then told me i have 100% health and 10 hours of battery life... only to soon die about 8 minutes later. any suggestions for this? i kinda think all hope is lost and i need to buy a new battery
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Godfrey said 11:17PM on 7-30-2008
Check you battery's stat... if it's
Godfrey said 11:19PM on 7-30-2008
Check you battery's stat... if it's <300 cycles I think you might get a free replacement from apple. (Yea I know, they said you can only get a replacement for <300 cycles and <70% health, but the "100% health" is obviously not accurate, something is wrong.)
julian said 3:39AM on 7-31-2008
well that sucks.... i was hoping i would get a replacement when this battery went bad since i have apple care for 4 years
... shes rip off
jerome said 10:45AM on 7-31-2008
Well, i have only 32 cycles on the battery and I had called them about 3 months ago to discuss a replacement. Apple did issue a battery recall, but mine did not fall into that category. When i called they said because mine was about a year old its typical for the battery to lose functionality over time. Unfortunately Apple Care does not cover the battery.
Damon said 10:15PM on 7-30-2008
Maybe that's why my battery exploded...
http://blog.ninthyard.com/2008/07/my-macbook-pro-exploded.html
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glebec said 10:22PM on 7-30-2008
Thanks for the tip to do this! However:
How exactly could a utility walk anyone through this? It involves physically plugging in and powering to full, physically unplugging and letting drain to zero, the user waiting 5 hours (while the computer is off an cannot give instructions), and then physically plugging in and not unplugging until fully charged. Software can realistically do a grand total of zero (0) of those steps.
Maybe it could hack the battery or PSU firmware somehow, but I'd be very leery of such a radical move when manually unplugging is so easy; and maybe it could provide persistent (annoying) reminders, like "don't unplug yet!," but it couldn't even do that for all steps (like waiting 5 hours before turning back on).
All in all I think this is a case where an app would be less helpful than the ordinary old printout of instructions.
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Godfrey said 11:25PM on 7-30-2008
No, I think he just mean a "calibrate my battery" button somewhere in the System Preference panel, which will bring up a wizard guiding the user through the process. Like, "Welcome to the battery calibration wizard" and explain to them what it is. Then, "Now please connect your power adapter to your computer." "Now your computer will charge, please DO NOT unplug your power adapter. You may continue to use your computer as normal, and we will notify you when you can proceed to the next step." and so on.
glebec said 11:28PM on 7-30-2008
I see. I guess this is just a rare instance where I don't agree that digitizing the information actually improves it substantially... it's such a basic process. On the other hand, setting a system reminder to do this might be a good idea. Adding an alarm now... Cheers, -G
Tom said 11:20PM on 7-30-2008
funny that you mention this because i just looked up this info yesterday. hopefully it fixes my battery and i don't actually have a dead cell.
it would read about 25% left and then just turn off; no sleep, no warning. when i'd plug it in, it would still read about 25%. so i decided to try this method. i let it get near that point again and just put it to sleep before i went to bed. now i've just woken up and plugged it in and turned it on and it reads 1% and charging. so far so good :)
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Jon said 11:34PM on 7-30-2008
I have a question...I have a late 2006 MBP and the battery has a current capacity of 48% with a charge cycle of 277...it says it's at 100% charge, but when I unplug it, the MBP lasts several minutes before shutting down. My question is if I take this into the Apple Store, will they replace it for me? I do not have Apple Care.
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matt said 12:07AM on 7-31-2008
No. It is out of warranty by about a year. If you're nice, they may offer a discount on a new battery, but they're not obligated to do anything but point you to the batteries on the shelf.
matt said 12:12AM on 7-31-2008
I should add that if your cycle count is below 300, you may have other options, including replacement.
Ed said 6:17AM on 7-31-2008
I had mine replaced with about 100 cycles and about 5 minutes of battery life. Just took it to the Apple Store and they did it, no questions asked really. Not sure if that was because it was under warranty or not, but I think you should be able to get away with it. Obviously if you have Apple Care you're fine.