MacBook Pro Late 2008 - Batterie almost down - is this correct ?

Question

Hi there,
I got a 15" MacBook Pro which I bought in May 2009. I have always done my best to keep the battery in good condition. Running it until the computer shuts off, charging it all the way, calibrating it twice a month and so on. Now it has 208 charging cycles and only 60% of the original capacity are left
Is the OK ? Apple says it´s supposed to have 80% after 300 cycles.
Thanks for your answers.

Answer 1

While a lot of talk about Li batteries makes it sound like a cycle is a cycle, not all cycles are truly the same.
Most Li batteries will actually decay more slowly with frequent partial discharge/charge cycles. Repeated or very frequent single use, full cycles will actually speed up the decline in your battery.
That's why it is unwise, and completely unneccesary to calibrate more than once a month (or, in my personal opinion, more then once very 2-3 months).
So, honestly, given what you wrote about your useage, and with 208 cycles, I would guess that you are seeing not unusual decline in battery performance.
Note too that heat also plays into it - if you use your machine a lot in hot and/or humid environments - that can accelerate the decay of a Li battery.
The 80% after 300 cycles information is really just an average, and certainly based on optimal conditions at all times. I have had heavily used Apple laptop batteries (i.e. used much as you've done with yours) die after 12-18 months of such use and at less then 300 cycles, they were useless. Others that I have, have gone well past 300 cycles and still been quite useable, but they were used differently (partial cycles, only calibrated a few times per year, only used indoors in climate controlled buildings).