[mcgarry101]

Hi

I am wondering if anyone can tell me what the norm is for the capacity of a macbook battery? I have had my macbook for just over 5 months now. When I first got it i was typically getting a duration of 4+ hours, however now I am getting 3 hours max! This 25% drop off seems quite big to me. iStat tell me it is at 100% health (at 88 cycles), but surely if it was 100% I wouldnt have lost a quarter of my capacity! I know using dvds etc uses more battery power, however I am not doing anymore with the macbook now than I was when I got it!
Is this the beginning of some fault? Should I contact apple?

[Simon]

Have you installed the most recent battery update?

Calibrate the battery.

Check full capacity (Sys Profiler > Hardware > Power > Battery Information). On new MBPs it should be ~4200 mAh. If it's less than 80% of that within the first 300 cycles you should get Apple to give you a warranty replacement battery.

[mduell]

Originally Posted by Simon 

Check full capacity (Sys Profiler > Hardware > Power > Battery Information). On new MBPs it should be ~4200 mAh. If it's less than 80% of that within the first 300 cycles you should get Apple to give you a warranty replacement battery.

Not necessarily:
b. Limitations The Plan does not cover:
(ix) Consumable parts, such as batteries, except in respect of battery coverage under APP for
iPod or unless failure has occurred due to a defect in materials and workmanship;

80% after 300 cycles is only a guideline. In the case of the iPod battery they make it clear that it must be under 50% for replacement, but they don't offer a specific guideline for Mac batteries.
Even the site you linked to says "You may choose to replace your battery when it no longer holds sufficient charge to meet your needs", not that they will replace it if it falls under the 80% with <300 cycles.

[Simon]

We're talking about MacBooks here. I have exchanged three MBPs batteries thanks to this clause. The Apple people on the phone are usually very easy going about it. You explain you have a 5 month old battery, inform them that you have calibrated and installed all the recent updates. Then you explain that your capacity is low (give them the numbers) and they will offer to send a new battery. They're usually very quick to offer help. No reason not to try.