how long does a mac book pro battery last?

MacBook Pros have used different battery technology since their introduction 5 years ago. Even screen size can affect battery life. Of course the big hitter is usage patterns, so what I get may be completely different from what you see.

The main factor is battery life is cycles count. YOU must be using the MBP on battery power a little every day even if you use it as a desktop machine. The battery must be used regularly of it will die an early death.

You should be doing 1-2 cycles a week. The concept of cycles is explained here:

http://www.apple.com/batteries/

Apple says a battery should retain 80 percent of it health (not charge) after 300 cycles. The batteries in my Late 2007 MBP have not been so gracious. The first one lasted 11 moths before leaking out at about 45 cycles; the second plummeted to only 50 percent health at 15 months and 60 cycles. Hopefully the newer models do better.

Probably the best explanation for battery life and health is this User-contributed tip:

https://discussions.apple.com/thread/1764220?threadID=1764220

Well worth the read.

My MacBook Pro 13" is now 15 months old and has completed 318 cycles, according to Coconut Battery and my system info. I timed it the other day, with normal use (writing docs, email and the occasional Internet surf) and in 2.5 hours it went from fully charged to turning itself off when the battery ran out of charge. I then left it for five hours before plugging in the adapter and it made no difference. I have the screen bightness set at 50% - anything less makes it difficult to use the screen

Yet Coconut Battery says the battery's current capacity is 5429 mAh, compared with its design capacity of 5770 mAh, so why the rapid drain?

I don't see anything in this discussion that tells me why - does anyone from Apple read these discussions?

Thanks

Allan Jones wrote:

Apple says a battery should retain 80 percent of it health (not charge) after 300 cycles.

That was true of the old removable batteries. The current unibody non-removable batteries are rated at 80% after 1000 cycles.

Battery life can be affected by charging habits and very much by operating temperture during charging. Frequent high temperatures when close to full charge can reduce life expectancy very quickly. See the table part way down on this page, which also has lots of great tips on battery life.

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batterie s

I have the same problem but i think mine is worst. I just changed my battery and in the space on 1 week its current max has decreased by 500 Mah. Its health is now at 92% i dont know why it is decreasing everyday