AMD — "We're Not Entirely Honest" About Batteries

Slatterz writes "In an apparent attack of the bleeding-obvious, an AMD rep has come clean and admitted (on behalf of the industry) that notebook and phone battery life figures are completely unreliable. AMD's senior vice president Nigel Dessau says that 'we are not being entirely honest with users about what PC battery life they can expect to actually experience.' He says AMD will now use a combination of idle time (where the machine is left to sit idle, and timed to see how long it takes for the battery to go dead), and 3DMark06 to measure battery life. Great in theory but some of the industry already bases battery figures on a two-test measurement, and the results are still wildly inaccurate."

Comments

battery runtime doesn't concern me as much as

[bensafrickingenius]

battery lifetime. I maintain about 200 laptops, and the damn batteries are usually completely useless after about a year. Oh, and of course, the laptop has a 3 year warranty, and the batteries have 1 year warranties. You can extend that to two years -- it'll only cost you about as much as a second battery would to do so.

It's not just batteries

[Weaselmancer]

I wrote a battery driver for a Windows CE device once. Here's how we did that.

There is an A/D line on the AC97 codec that we use as a measurement probe to the battery. Used that to determine the actual voltage being seen. Charged the device 24 hours, and ran a program that dumped that output to a file until it died.

Then fit a third order polynomial to the data. We use that to predict where you're at percentage-wise on the draining curve. Then we made the mistake of looking at the metrics for other batteries we got from the manufacturer.

As it turns out, the characteristics from one battery to the next varied wildly. Even after you average a dozen or so batteries you'd still get better results throwing darts at a dartboard.

In short, that 3DMark06 test is probably reading battery capacity from something similar. That would be worth looking at for another source of possibly bogus readings.