Check your battery's health with System Profiler

If you use a Mac laptop, take a look at System Profiler to give it a battery health check.

Check your battery’s health with System Profiler
Mac Tip #354, 03 September 2008

Black MacBook - open

A new Mac laptop, such as a MacBook Pro or a MacBook, can run for maybe 3 or 4 hours on battery. After a while though that fully charged battery will last for only 2 hours, then 1, until eventually it just dies.

That’s the way of all rechargeable batteries — they have a certain number of ‘cycles’ in them. As the months go by the battery’s capacity gradually declines.

Back in Battery check, Mac Tip #260/13-Sept-2006, I explained how to use the button on the battery itself to check the charge. System Profiler gives you more detailed information: the number of charging cycles, the make of the battery, the capacity and so on.

Open up Applications > Utilities > System Profiler. A window appears showing information about your Mac.

Click on Power, under Hardware in the list of Contents on the left of the System Profiler window. Battery and other Power Settings information is displayed in the right-hand pane.

Brand new Apple battery - information.

The Model Information section shows the battery’s serial number, manufacturer and other data about its manufacture.

The Charge Information and Health Information sections are the ones to monitor.

A charge cycle is when the battery is run flat and then recharged to full. If you run the battery partly down and recharge it, that counts as part of one cycle.

The battery’s capacity to store a charge is measure in Milliamps Per Hour (mAh).

Click the screenshots for larger versions.

In the first screenshot I can see that my brand new battery has been discharged and recharged 3 times (Cycle count: 3). It’s fully charged and has 5417 mAh capacity remaining. Its Full charge capacity is 5454 mAh. The Condition of the battery is listed as: Good, under Health Information.

Possibly faulty 3rd party battery - information.

The 3rd party battery (ie, not from Apple) in the second screenshot has been discharged and recharged 49 times (Cycle count: 49). It’s fully charged but has only 1673 mAh capacity remaining. Its Full charge capacity is only 1680 mAh. The Condition of the battery is listed as: Check battery, under Health Information.

This battery seems to have a problem. It hasn’t been used very much but its capacity is very low. I suspect a problem with it and have contacted the supplier for support.

If you use a Mac laptop, take a look at System Profiler to give it a health check.

Update: I’m using Mac OS X 10.5.4, Leopard. Older versions of the Operating System may have less Power information, or maybe none at all.

Tagged as: battery, capacity, charge, power

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* 6 comments… read them below and tell us what you think.

Peter Rankilor 1 6 January 2009 at 23:29:10: Thanks for this useful explanation.

Maddy 2 25 January 2009 at 23:26:05: MY cycle count is 319. Im getting some 1 Hour battery life. Before i had 4 hours of battery life :)

Massimo 3 19 January 2010 at 00:18:26: My cycle count is 376.. after how many cycles does the battery has to be replaced?

My battery life lasts about 1.5 hours.. not much !!!

Need some advice.. I am considering replacing the battery but is quite expensive I believe.. I have tried different settings to increase h the battery life but is not making much difference.. battery still runs out quickly.

Massimo 4 19 January 2010 at 00:28:46: Also I don’t know whether charging the battery to its full is damaging or not?
Is it better to charge it up to 70 – 80 % and then use it?

Paul H. 5 19 January 2010 at 04:31:05: I have been charging and using my MacBook for about 2 years now. I still get 3 hours or more of battery. One thing though, about 1 year into having it, the battery terminals on the battery side started corroding or something. They gave me a shiny new battery! I have about 350 charge cycles on this one.

Miraz 6 19 January 2010 at 15:44:51: Massimo: I’d say you’re doing pretty well on your battery with 1.5 hours for 376 charges.

My battery has 79 cycles and currently shows around 1.5 hours remaining.

The amount of time any on full charge gives you depends a whole lot on what you’re doing – eg reading, typing, playing music – and on what services you’re using – eg wireless, backlight and so on.

Apple suggest you fully discharge the battery around once per month and fully recharge it for best maintenance. There’s no problem with charging it fully.