This is perplexing me.  My MBP is less than 1 year old (11 months) and it just started having really a short battery life this week.  This happened suddenly.  Last week I could go several hours.  This week the batteries life is sucked out of it in about an hour or less.

I have a 15.4" MBP that I bought new last February.  I use it every day for programming and internet.  The battery has 121 cycles on it which isn't that many according to Apple.  I do have the Apple Care Package and I may be talking to them before the 1 year mark.  

I normally run plugged it and only use the battery on rare occasions.  I may run on battery a few times a month.  This week, while in a meeting at work, I watched the battery die in about an hour.  This has never happened before.

I just started a life test battery drain down.  I'm timing in 5 minute intervals the battery life remaining while it sits idle running on battery.

I have a few apps running but nothing big, email, a news reader, Firefox, Texteditor and the system monitor.  I have the display dimmed to 75% brightness, Bluetooth is off (as normal) and the Wi-Fi is on (as normal).  I had to shut down Twirl since even at idle it sucked 5-10% CPU usage. Anyone have a clue as to why that is?  So I killed it to see if it did any better since lately I've been Twittering a bit more.

The CPU at the moment is sitting at 95% to 98% idle.  So far at the 1/2 hour mark the battery is down to 70% and this is while idle.  When I'm doing normal work it has been draining much faster.  My second battery life drain test will be done while I'm using it as normal.  I'm sure it will drain much faster then.

My normal usage is web application development.  I use CFEclipse, email, browse the web, read news and code my ColdFusion stuff.  When I’m coding I have Coldfusion 8 running, but that only uses the processor when you test a page.  The same is true for my development PostgreSQL DB server that runs on here.

What is proper battery usage?  This varies by battery type and manufacture.  Li-ion (Lithium Ion) batteries are touchy buggers.  They do not like freezing or overheating.  Both of those are the fastest ways to destroy a Li-ion battery.  They also do not like full discharges.  I'm not sure why that is, but everything I've read about Li-ion batteries says to not do that.  Some sites even claim that a fully discharged Li-ion battery is ruined at that point.  They also claim is that Li-ion batteries don't have 'memory' and don't need to be fully discharged before charging like other types of batteries.

My battery drain down went ok; I had an interruption so I put it to sleep in the middle.  That does not seem to affect the overall results.  While on battery and with the CPU at idle it went down to a 23% charge in 1 hour and 40 minutes with a 36 minute sleep period.  During the sleep period the battery went from 51% to 39%.  That seems more than a little strange to me. 

I stopped the test at 23% since as I mentioned Li-ion batteries do not like full discharges.  So after it fully charges I will do the test again while actually using it.

I'm back and the battery is fully charged again.  So at 8:00pm I pulled the power cord and let it run on battery while researching batteries more and getting some applications to help inspect the battery itself.  I really like CoconutBattery. This little application reports your batteries life now and what it was when new.  Plus if you start using this application with a new battery you can have it save the reports over time so you can record the decline of your battery over time.

So my test is done.  That did not take long at all, 44 minutes from 100% to 19% and the low battery warning. 

8:00pm    100%
8:10pm    87%
8:20pm    72%
8:30pm    57%
8:40pm    41%
8:44pm    19% - low bat warning
 

CoconutBattery is also reporting that my battery when fully charged is less than 26% of it's original capacity.  New it would provide 5600mAh of power and now it only has 1495mAh of capacity. Remember that I only have 122 cycles on it and from what I have been reading is that it should be good for 300 cycles and Apple refuses to replace them if they have more than 300 cycles.

I will be visiting the Apple store tomorrow.  This battery will not survive the week at this rate.  They better give me a new one, there is no reason why a non-abused battery should fail so fast.

 After some research and finding coconutBattery I am no longer perplexed.  I can see my battery is shot.

UPDATE: Went to the Apple sore today.  They tested the battery and sure enough it was shot.  When they got to it the battery was at less that 950mAh at full capacity.  They swapped out the battery for a new one on the spot.