Comments on: OLPC battery life: What's the real story?

Dig enough, and you'll finally get a reality check on the claim of 12-hour battery life from the One Laptop Per Child project.

[Charbax]

There is a black and white low power mode..

And I think they only recently started optimizing the DCON process that shuts off the main CPU most of the time when it's not needed, saving a lot of battery time.

The black and white mode reflective mode consumes much less power, so the numbers might be in such e-book mode when DCON will be kicking in to put the main CPU on stand-by mode.

[Peter N. Glaskowsky]

Good points

If the CPU is running without benefit of power management-- like PCs often do before OS-based power management kicks in-- then perhaps these test systems are consuming a couple more watts than they ought to. But this also means the OLPC must be a long way from being production ready.

The backlight issue is another good point, since the tests were performed with the backlight on-- but the most common operating mode of the system will be indoors with the backlight to get a color display, so I'd have to count this as "heavy use" in the sense of the original 10-12 hour claim. Reading a book outdoors in sunlight isn't heavy use by any standard (and I doubt anyone's going to spend even 4 hours a day doing that anyhow).

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[Jim Gettys]

Ebook mode lifetime - > 13 hours.

Yes, we are not finished with power management. There are several major power savings yet to be had, when running in typical operation.

The major feature we have is the ability to read books (screen on, but processor suspended). In this mode with the screen on (something unlikely to be the case for any human I've ever seen). I have measured this at over 13 hours, occasionally flipping pages (the system wakes up extremely fast).

[Peter N. Glaskowsky]

Thanks for the info

I also appreciate all the additional data you provided in email, and I'll post a follow-up soon.

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