Lies, Damn Lies, and Battery-Life Statistics

theodp writes "What if automakers measured gas mileage by rolling their cars downhill with their engines idling? They might, Newsweek's Daniel Lyons suggests, if they took inspiration from the MobileMark 2007 notebook battery-life benchmark test, the creation of a consortium called BAPCo, whose members are — surprise — computer makers and other tech companies. Laptops score big numbers, Lyons explains, because they're tested with screens dimmed to 20%-30% of full brightness, Wi-Fi turned off, and the main processor chip running at 7.5% of capacity. Professional reviewers see company-generated battery-life claims as a joke. 'The rule of thumb is that in real-world use you get about 50 percent of rated battery life,' says a Gizmodo associate editor. Leading the call for reform is the not-necessarily-altruistic AMD, who gripes that MM07 was created in Intel's labs and rigged so Intel chips would outscore AMD chips, which draw more power when idle."

Comments

Re:Apple Don't

[wnknisely]

For what it's worth, I'm seeing numbers comparable to these on my new Macbook pro. Perhaps Apple is using a different benchmark than the one in the article above?

Re:Hate to sound like a Mac whore

[OrangeTide]

I got my Macbook because it makes a pretty decent Linux box (although I now dual-boot OSX because Apple has slowly wormed its way into my life), and the lowest end Macbook is pretty affordable. Comparable in price and specs to a mid-range laptop. And yes it does get good battery life (the battery life is better in OSX than in Linux though)

If you use computers the way I do, the you can really get those 4 hours that those cheap PC laptops claim. I use it in the dark(so screen dimmed), no WiFi, command-line only running a text editor for Vi. Occasionally kicking on the CPU to compile a .c to a .o and link the .o's (using 'make' saves a tremendous amount of battery life). My Macbook got a little over 5.5 hours for me on a flight before it had to shut down(just writing code and reading man pages). If I would have sprung for the Macbook Pro it would have been more like 7-8 hours though.

Already have that

[SuperKendall]

If someone comes out with a spare-battery-attached-to-a-magsafe-connector for those die-hards who absolutely *need* it, angels may sing in the treetops

This is exactly why I don't understand the fuss over non-removable batteries. You get better battery life, and if you need extra power you've always been able to buy external battery packs. They have cable that attach to the Magsafe connector. You can get them in a range of sizes, including sizes that are not much larger than a spare battery would have been anyway...

Similarly there are tons of external packs for smaller devices like the iPhone/iPod (or anything usb charged).

I also have not often found the need for an second battery in a laptop if I can get at least three to four hours out of it. Basically the only time is an international flight, and for that the external batteries are perfect. Heck, until it broke the Solio solar powered recharger I had could even recharge itself in-flight as long as I was at a window!!

Re:Apple Don't

[speculatrix]

there's no point in ordering a *spare* battery when you buy a laptop; ordering a *second* battery because you're travelling a lot might make sense. this is because LiIon batteries age, and you can only slow down the ageing by keeping them 40% charged in a moderately cool place.

LiIon batteries also lose capacity after a number of charge/discharge cycles, the number varies according to how deep the cycles are and the temperatures you reach in the process. When the battery packs are particularly expensive - think Prius and other electric cars - the battery management electronics are crucial to protecting the investment, and the batteries are never run anywhere near flat and particularly are never fully charge to prevent some cells overcharging, and the charge/discharge controlled carefully to prevent temperature rises leading to premature ageing.

thus, in conclusion, keep your laptop battery cool, don't thrash its battery, don't deep cycle it, buy a good brand so you can buy a new battery *in*the*future*not*for*storage*.

Re:Apple Don't

[moosesocks]

All of these things are true for Lithium Ion batteries.

However, Apple's current line of notebooks use Lithium Polymer instead of Lithium Ion. Additionally, the charging circuitry is supposedly much more sophisticated.

I'm not sure if the modes of failure for commerical Li-Pol packs are well-known at this point, and I have no reason to believe that they'd be the same as those for Li-Ion.