[HarryT]

Originally Posted by Nate the great

There is a competing technology: LCD.

The only real benefit of Eink is it uses less energy than an LCD. But if you have the Eink screen in a reader with a moderately powerful CPU, the power savings are negligible. Most of the power is consumed by the electronics, not the screen.

I must respectfully disagree, Nate. The point about an eBook reader is that it spends 99.5% of its time displaying a static image, and the screen uses no power to do that. During that time, the CPU can "hibernate" and again use very little power. LCD screens constantly use power.

So far, the only device that actually showed the benefit of an Eink screen was the PRS-500. Mine had a 3 week battery life. (I think the reason it had such great battery life was good hardware design, not the screen.) The Cybook and Kindle get about a week, and from what I've heard the 505 gets around 2 weeks.

Those are "standby" times, and don't really reflect usage. I can get about, say, 25h of actual "reading time" on my Gen3, on a battery charge. That's a 1000mAh battery - less power than that of the typical "AAA" battery. That's at least a factor of 10 better (probably more like a factor of 20) than any laptop computer with an LCD screen.

I have several devices that have a battery life of a week or more. Almost all have LCD screens.

Is that "standby time" or "usage time" of such devices? What's the battery capacity?

The only devices I can think of which have remotely comparable battery times were the old mono "PalmPilot" PDAs, which would run for weeks of a couple of AAA batteries. Their screen size, however, bears no comparison to that of a modern book reader.