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."

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.

Re:battery runtime doesn't concern me as much as

[T Murphy]

New zinc/silver batteries are well in development. One company (http://www.zpowerbattery.com/ [zpowerbattery.com]) is planning on a business model that although the initial cost is much higher, the batteries can be recycled, so by exchanging old for new you come out ahead, and the batteries have more recharges than Li batteries. Some students in a class I took last quarter did a poster on these batteries, and I'm looking forward to replacing my current battery that took a year to cut charge life from 2 hours to 20 minutes with something other than another Li battery. No, I'm not a shill, I just hate the current batteries like the average /.'er loves to hate M$.

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.

Re:battery runtime doesn't concern me as much as

[Anonymous Coward]

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.

That has also been my exact experience with the 100 or so laptops that I maintain.

Re:battery runtime doesn't concern me as much as

[Dan Ost]

My experience has been that a new battery that gives 3 hours up uptime gives 2 hours after a year and less than an hour after 3 years. Of course, our laptops are used mostly when docked, so we don't cycle our batteries as often as we could.

Re:Not that big of a deal

[PitaBred]

That's because the EPA recently changed how they calculate MPG ratings [blogspot.com], making them more "accurate" with real-world usage

Re:Exactly like MPG estimates

[Madball]

It's no different than the automobile industry stating "EPA Estimated MPG city/highway" which is not based on a dynamometer test

EPA tests are done on a dyno: http://www.fueleconomy.org/feg/how_tested.shtml [fueleconomy.org]

or actual performance measurement but instead is calculated based on the amount of CO2 which exits the exhaust pipe of the car! Is it any wonder, then, that hybrid cars which shut off their gasoline engine when stopped and at low speed/light acceleration, would give grossly inflated figures? Well, they did (and do), which explains why real-world MPG is often far less than this calculated (not even simulated) performance.

Why do you think that the testing methodology inflates the estimated mileage for Hybrids because of shut-off's at lights? If your gas engine is shutoff, how much fuel are you burning? Zero. If you are driving a conventional powertrain vehicle and are idling, how much fuel are you burning? Something more than zero. Granted, the crux of the matter is measuring what this something more is, but that's on the conventional side, not the hybrid side of the equation.

What is needed is real-world testing -- dynamometer ("rolling test track") testing for autos where the wind resistance, temperature, barometric pressure, etc. can all be carefully controlled.

And how would you test wind resistance on a dyno anyway? Since the vehicle isn't physically moving, drag is a non-factor (and thus "strictly controlled" at zero).