Alternative power/recharging source?

[david at lang.hm]

On Fri, 22 Feb 2008, Richard A. Smith wrote:

> david at lang.hm wrote:
>
>>> Again whats your source for this info? Because its news to me.
>> 
>> http://laptop.org/en/laptop/hardware/specs.shtml
>> LCD power consumption: 0.1 Watt with backlight off; 0.2-1.0 Watt with 
>> backlight on;
>>
>> David Lang
>>
>
> You are misinterpreting that. That is the display _only_.  Not the system 
> power.
>
>> in full e-book mode the display unit is the only thing getting power (radio 
>> off, cpu fully suspended)
>
> And the EC, the memory, various pull up/down resistors, and few other suspend 
> voltage regulators.  All these add up to a non-trivial amount.

you are not nessasarily going to be powering the system memory

> Claiming that the power draw of the display unit in e-book is the system of 
> draw of the laptop is inaccurate.  It will be close if you were to throw up a 
> page and let it sit there and never touch it.  But the moment you engage the 
> cpu to flip a page you draw 5-7x more power.  The average  draw then depends 
> on how may pages you flip.  We do not yet have any metrics for what that will 
> work out to be.

if you flip one page every 5 seconds (a pretty fast reader) and for 1 
second the system eats 5x the power of the display you end up with 0.2w of 
power.

the rest of my quote that you clipped said that in full e-book mode the 
power consumption was ~0.2w.

however, the initial source of the data was a presentation by Mary Lou 
Jespin at Usenix last year. however I can't just cite my memory, so I went 
looking on the website and found that snippet of information.

however, it almost doesn't matter which of us is right. the mere fact that 
we are having this disagreement indicates a need for better documentation 
of this sort of info.

David Lang