January 14th, 2009
Apple's 8 hour battery: breakthrough or bungle?
The new 17″ MacBook Pro has a non-removable, 8 hour battery that Apple claims can recharge 3x more times than standard batteries and has a 5 year life. Are they nuts?
The “removable” battery mistake
Removable batteries are a kludge, not a feature. The only reason you want a removable battery is that a single battery’s life is too short.
Apple says that they were able to expand battery size by 40% by making it non-removable. Battery size translates directly into battery life.
Update from ZDnet’s own Jason D. O’Grady:
- There are three tri-wing screws holding the battery to the Unibody case. Apple did this to intimidate people out of swapping the battery, but a small flathead screwdriver works fine to remove the screws.
- You can replace the battery by removing 13 screws and a replaceable sticker.
- The battery is HUGE. It weighs 20.1 ounces (1.25 pounds). That’s 20% of the computer’s weight!
End update.
As Apple’s excellent battery video (click on “Watch the battery video”) points out, removable batteries require a lot of space for connectors, latches and support. Lose the support bits - build a bigger battery.
So?
An 8 hour battery life totally changes the user experience: instead of counting minutes and looking for outlets, your notebook is always ready when you are. A few hours doesn’t seem like much, but in practice the difference is huge.
How do I know? For 5 years I carried a notebook with a 9 hour battery life and a reliable sleep mode. I’d walk into a meeting, open the book, and be right where I’d been hours before - and I never had to jockey for power.
No notebook since - with 3-5 hour battery lives - has given me the same sense of freedom. The reliable Mac OS X sleep mode and an 8 hour battery life will be all most professionals need to get them through the day without rebooting or plugging in.
The 5 year/1,000 recharge battery life?
Apple further claims that the battery can be recharged 1,000 times, while maintaining 80% - 6.5 hours - of battery charge. Part of the magic is “advanced chemistry” in the lithium batteries.
The other piece is “adaptive recharging” which “. . . reduces the wear and tear on the battery . . . .” Really?
Really! According to a 2000 patent (6,204,634) issued to The Aerospace Corporation, a manufacturer of low-earth orbit satellites federally funded research and development corporation in support of DOD and intelligence community national security space programs:
Existing charge control systems . . . typically utilize voltage-limited constant current charging of individual cells to maintain an adequate battery charge while also limiting cell degradation rates. . . . Ultimate cycle life has a strong inverse correlation with the cumulative amount of overcharge put into the cells by the charge control system. The optimum cycle life is achieved when unnecessary overcharge is exactly zero.
In addition, degradation rates can change significantly as the electrodes transition among several charge states. Also, the recharge voltage limit shifts as the cell temperature changes and as the cells degrade over life.
Translation: yes Virginia, l-ion battery charging can be optimized if you spend money for the sensors, algorithms and local intelligence to do it.
You won’t see that on your $500 Wintel notebook any time soon.
The Storage Bits take
Good products serve; great products surprise. For a generation that has never known more than 4 hours battery life, the new 17″ MacBook Pro will be a revelation.
Assuming, of course, that it lives up to its billing.
Comments welcome, of course.
Robin Harris has been messing with computers for over 30 years and selling and marketing data storage for over 20 in companies large and small. See his full profile and disclosure of his industry affiliations.
Subscribe to Storage Bits via Email alerts or RSS.
| 01/18/09
