If, like me, you get easily confused by the recent wave of ultra-cheap ultra-mobile announcements, you may enjoy this comparison chart I just posted at the MobileRead wiki.
Ultra-mobiles make great potential e-book readers, but until recently these devices were marketed (and consequently specced) as high-end machines. They would come equiped with power-draining features that you really do not need to read an e-book. This new generation of subnotebooks, such as the announced Asus EEE and VIA Nanobook, is deliberately lighter specced, and might introduce an era of light devices with good battery performance.
3 hours (Asus EEE) is good battery performance?
For this audience, it’s worth noting that the OLPC in “reading mode” is designed to pull less than 1 W of power, and with a 22.8 Watt-hour battery, might go for as long as 20 hours if you’re only using it to read local ebooks.
There’s also talk of a 16 Watt hour battery. The screen itself is only responsible for a third of the power requirements in the OLPC laptop.
As I wrote on the wiki, “strictly speaking this would mean that the Asus device does not belong on this page, because of its poor battery performance”. I do think it belongs alongside the devices listed there, though.
From [OLPC information]:
Battery:
Pack type: 4 or 5 Cells, 6V series configuration
Fully-enclosed “hard” case; user removable
Capacity: 22.8 Watt-hours
Cell type: NiMH (or LiFeP)
Pack protection: Integrated pack-type identification
Integrated thermal sensor
Integrated polyfuse current limiter
Cycle life: Minimum 2,000 charge/discharge cycles (to 50% capacity of new, IIRC).
[Moderator’s note: URLs at the top may confuse WordPress a bit, at least as displayed in some browsers–hence my edit of Bill’s helpful comment. – David]
“In one test–with the caveat that the the WiFi was off, an XO ran for 23 hours on a 92% battery charge.” — from the May 19 OLPC newsletter
Well yeah, I want one! 🙂
The hardware specification at the OLPC wiki, under battery:
As I explained in a footnote at the Mobileread wiki, I used the most conservative estimates, except for pricing. That way I hope to avoid getting into a situation where I accidentally mix and match a manufacturer’s most rosy projections. 16.5 Watt-hours, with a usage of 3 Watt (1 Watt for the colour screen, 2 for the rest of the system) results in a usage time of 5.5 hours. Or at least, so I hope; I am strictly an Arts ‘n’ Humanities type of person.
From what I understand, the OLPC laptop uses even less if you switch it off. I am not trying to be facetious: when switched off, the device still operates, as a node in a mesh network, and therefore still uses electricity.
Hmmm, trusting information you find on wikis… :-).
I believe it has (sort of) three modes: full on, which draws about 3W, ebook mode, which draws a little under 1W, and mesh network support mode, which draws about 300mW. Or you can turn the radio off, which should make the power draw effectively zero.
“Hmmm, trusting information you find on wikis”
I’d say about as reliable as the official information most manufacturers hand out. 🙂