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These comparisons are far too simplistic. It should be noted that even when considering a single device, such as a standard PC computer, power usage can vary a great deal between different software applications. Right now I am typing a message in a browser, so CPU, disk, etc. most components are not busy, hardly doing anything at all. Right now my LCD screen uses the most power. When I start a new build or any other CPU intensive processing then suddenly CPU could be drawing more than the screen. When you play an action game then between your CPU, GPU and disk they will draw far more power than LCD display!!!!
That means having a lower power display may sometimes provide a much longer runtime (when display uses most power) and other times may not (when other components use more power).
Now we come back to eReader vs mobile phones (tables and UMPCs are still limited to perhaps 5 hours, so not much better than regular laptops). You are comparing DR rendering PDF documents against a mobile phone rendering plain text. In general mobile phones run simple small apps, nothing even close compared to the complexity of rendering PDFs. In fact, you should understand that PDF rendering is far from trivial. Therefore, DR CPU is using far more power on average while rendering PDF docs compared to mobile phones doing very simple rendering of icons and simple text. DR is doing far more work. So clearly when DR is tasked with heavy duty computations such as PDF rendering then despite a low power screen it still needs power for CPU.
The point is, compare runtime between DR and mobile phones doing the same work, rendering PDF docs!!!! Then let's see how their runtimes compare.
Even comparing DR and Cybook is not fair. Cybook crashes for any non-trivial PDF. So it has a smaller CPU using less power, *BUT* cannot handle compex context and is much slower rendering content than DR.
I think DR is getting too much flak for this battery issue. I think iRex for the most part made all the right choices. DR needs a more powerful CPU to handle more complex PDF content, despite using more power. It is unfortunate they slipped on battery and power mgmt. Either power mgmt is mandatory and in V1 or they offer options for battery (2x builtin, 1 options, whatever) They clearly understimated this area.
But hey, most manufacturers make the exact same mistake. Most laptops have small batteries. They cannot handle the load and end up lasting only couple of years, then capacity degrades rapidly.
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