Over the last couple weeks, I've been going back and forth with readers who truly believe that Snow Leopard is reporting battery errors when they have a perfectly good battery. There's even a substantially large thread in Apple's Discussions forums about this topic. I've been notified of that thread many times, accused of not covering real issues, hiding the truth and just plain refusing to believe that it's an issue with the Operating System.
After trudging through all of that, I've determined that it's a whole bunch of hoopla. I'm not saying that some of these people aren't experiencing real issues with the software -- just the sheer amount of complaints in the discussion forums would say there are problems -- but the "Service Battery" complaint doesn't appear to be related to software issues at all.
One of the big differences between Leopard and Snow Leopard is how they report issues with the battery. Leopard didn't report issues in a place where most users would know to check: System Profiler - Power - Health Information. Snow Leopard reports issues directly from your Menu Bar as shown in the picture. This difference caused a real stir in our tips box because many users never knew that their batteries were bad before Snow Leopard. "My battery isn't bad, it worked fine until I installed Snow Leopard" -- Yes, it may have worked fine but that doesn't mean it didn't have issues before the upgrade. Apple just made the problems more noticeable in the OS. In fact, they're helping their users catch them sooner.
Most of the time, people don't realize their battery has issues until it REALLY has issues like 20 minute run-times, random shut downs, the black "x" in the battery icon, etc. All of these are issues we (technicians) use to identify a bad battery. These new battery checks could actually help you find out your battery is bad before the warranty runs out; before it gets to the point of no return.
Genius Bars and Apple Authorized Service Providers now have a special utility that actually reads the health information directly from the battery and can determine why the Operating System says the battery needs serviced. Most of the time the problem will fall into two categories: battery failure or depletion. This diagnostic tool is actually a game-changer in the world of Apple's battery warranty: batteries are no longer automatically covered through the first year. If the battery legitimately fails, they'll replace it free of charge. If you happen to deplete the battery within the first year, you'll pay for a new battery.
Take all of this information with a grain of salt. Apple IS helping us by having the OS show us when the battery fails, but they've also made warranty battery replacements a little more fair on their end. Having blanket warranties for a year probably cost them a lot of money considering it's pretty easy to deplete a battery within that time if you don't take care to keep it healthy.
I've had the battery in my MacBook Pro for 9 months now. I have 245 cycles on the battery, 3-4 hours of pretty heavy usage (without the killer graphics enabled), and 99% health rating according to iStat Pro. I'll leave you with a few tips to help maintain the health of your battery:
- Never leave the machine plugged in all the time. Laptops are meant to be portable. Using it as a desktop that never runs on the battery will destroy your battery life.
- Cycles are your friend. Never letting the battery complete a cycle will greatly diminish your run-time. Try to avoid charging the battery unless it's drained past 30%. Any time the battery drains past 50% and charges more than 50% counts as a cycle. The farther you let it drain before the charge - the better its overall health will remain.
- 30 cycles in a year is not a good thing. ;)
- Let the battery drain completely a few times a week.
- Never let it sit for long periods of time without use. Batteries need to be loved or else they won't love you.
UPDATE -- There have been a lot of opinions expressed in the comments about the proper care and feeding of Apple laptop batteries, especially the newer lithium ion units. I'm happy to see that this article sparked such a healthy debate. To be clear, my tips here are not directly based on Apple's recommendations. They are driven by my personal experience servicing Apple laptops and Apple batteries for customers, and my own battery health history. For a different take on proper battery care for modern gear, we were pointed to feedback from Marco Ament that's worth a look. If we have electrical engineers or battery designers in the audience that wish to weigh in, we'd be happy to hear from you.