Apple Notebook Battery FAQ

From Mac Guides

This Guide was created by stridemat and is based upon a forum post by GGJstudios

1 Battery life from a charge
2 AC power
3 Calibration of newer unibody models
4 Battery lifespan
5 Batteries are not covered
6 Bulging or swelling battery
7 Further Information

Battery life from a charge

Apple's advertised claims about battery life from a charge are based on very specific conditions, which are very likely less demanding than your normal use.

Your battery life is dependent on many factors, including screen brightness, WiFi, bluetooth, apps/processes/widgets running, Flash content on websites, graphics-intensive applications, etc. Even if you're not getting anywhere near the advertised life from a charge, it's most likely quite normal, and simply the result of your usage demands.

Your "time remaining" indication is an ever-changing estimate, based on the current workload of your system. It will fluctuate up and down from minute to minute as your power demands change. It is not perfectly accurate, but only an estimate.

To control what Flash content plays on websites, use ClickToFlash plugin or ClickToFlash extension.

Use the YouTube HTML5 Video Player instead of watching YouTube videos in Flash, when available. Not all YouTube videos are available in HTML5, but when they are, it will reduce power requirements.

If you're using a MacBook Pro with both integrated and discrete graphics cards, you can install gfxCardStatus to manually select your integrated GPU, which will help reduce power demands and give you more life on a battery charge.

Apple Portables: Battery terminology and key concepts

Sleep drain: You may notice the battery in your Apple portable may drain up to 1% per hour (24% per day) while the computer is in sleep mode. This is normal behavior.

If you find your battery has drained more than around 1% per hour of sleep, it's possible that your Mac didn't stay asleep the whole time. Mac OS X: Why your Mac might not sleep or stay in sleep mode''

MacBook Air models from Late 2010 and newer are designed to go into standby mode after an hour of sleep. In standby mode, your battery should last about 30 days. For more information read this: MacBook Air (Late 2010) and later: About standby mode

Which Mac model you have and which version of Mac OS X may be factors in determining battery life. According to the test results posted here, battery life may improve by running Lion on a newer MBP, but may be worse on older models. Your results may vary.

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AC power

Apple does not recommend leaving your portable plugged in all the time. 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.

Also, it is not recommended to run your Mac on the AC adaptor with the battery out (Of course, this only applies to removable batteries).

If the battery is removed from a MacBook or MacBook Pro, the computer will automatically reduce the processor speed. This prevents the computer from shutting down if it demands more power than the A/C adaptor alone can provide.

While you can't remove the new built-in batteries, this method of using both AC power and battery during periods of peak power demands is still applicable. This is why you may find your battery may temporarily stop charging or even drain somewhat, even though you have your AC adapter plugged in. This is working as designed and will only be used during periods of peak power demands.

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Calibration of newer unibody models

The built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require regular calibration like the removable batteries. For models that require calibration, see the CALIBRATION section below.

Portables with built-in batteries

Current Apple portable computer batteries are pre-calibrated and do not require the calibration procedure outlined in this article. These computers use batteries that should be replaced only by an Apple Authorized Service Provider.

MacBook

MacBook (13-inch, Late 2009) and later

MacBook Air

MacBook Air, all versions

MacBook Pro

MacBook Pro (13-inch, Mid 2009) and later
MacBook Pro (15-inch, Mid 2009) and later
MacBook Pro (17-inch, Early 2009) and later

If you suspect your battery readings are inaccurate, calibration won't harm your battery and will make your readings more accurate.

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Battery lifespan

Be aware that your battery doesn't stop working if the health drops below 80% or if you exceed the number of cycles listed here. You can still use a battery with 79% or lower health or 1001+ cycles, as long as it still holds a charge. If you have a battery that has failed to meet its expected lifespan, assuming your battery is properly calibrated (for those models that need calibration), you may have a defective battery. If so, contact AppleCare to see if they will replace it.

For the newest generation of batteries (Late 2010 and later):

The built-in battery of your MacBook, MacBook Pro or MacBook Air is designed to deliver up to 1000 full charge and discharge cycles before it reaches 80 percent of its original capacity.

For earlier models:

For Apple notebooks with removable batteries — such as previous generation MacBook and MacBook Pro computers — a properly maintained battery is designed to retain up to 80% of its original capacity at 300 full charge and discharge cycles. You may choose to replace your battery when it no longer holds sufficient charge to meet your needs.

The built-in battery of the MacBook Air is designed to retain up to 80% of its original capacity at up to 750 full charge and discharge cycles.

The built-in battery in the new 13-, 15-, and 17-inch MacBook Pro is designed to retain up to 80% of its original capacity at up to 1000 full charge and discharge cycles.

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Checking status and health

To check battery status, use iStat Pro or coconutBattery (has some inaccuracy issues) or iStat Menus or  > About This Mac > More Info... > Hardware > Power > Charge Information:

Your battery health is referred to either as a percentage or in mAh and represents your current full charge capacity (mAh) as compared with the ideal full charge capacity (100%). Be aware that battery readings are not 100% accurate and they fluctuate up and down, so if your brand new battery health is somewhat more or less than 100% or if it fluctuates up and down over time (100%, 91%, 95%, etc.), don't worry. It will not only decline. For example, if your battery health is 92% one day, it could be back up to 97% a few days or weeks later. It is not a one-way fluctuation. This is completely normal.

If your Mac shuts down without a low battery warning, read this:

Apple Portables: Low power warning does not appear while running off of the battery

"Replace Soon" "Replace Now" "Service Battery" "Normal" "Good"

Leopard users may see their battery reported as "Good", while Snow Leopard and Lion users will see the same condition reported as "Normal". They mean the same thing. For the other conditions reported under Snow Leopard: Mac OS X v10.6: About the Battery menu bar extra for portable Macs

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Charging

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What is a "cycle'

Determining Battery Cycle Count

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.

So a cycle could be draining the battery all the way and recharging, or draining/recharging it 25% four times, or draining/recharging 10% ten times, etc.

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Calibration

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Batteries are not covered

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Bulging or swelling battery

If you find your battery bulging or swelling, it is highly recommended that you replace it before it causes damage to your Mac. The bulging or swelling may or may not be due to a defect in the battery. Contact Apple to see if they will offer a replacement.

MacRumors threads about bulging or swelling batteries.

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