harvesting energy

[Paul Fox]

alan jhonn aguiar schwyn wrote:
 > 
 > 
 > I think that not is for "an adult athlete"...
 > In Uruguay, in a site that not have electricity.. The childrens use this 
 > dispositive..
 > And not need much effort than ride bikes for a while...
 > Regards
 > Alan


bear in mind that the *minimum* time it takes to fully charge a single
XO laptop is roughly two hours.

once you're providing all the power the laptop can take at any one
time, providing more (i.e., by being a stronger athlete) doesn't do
any good (unless maybe you want to charge two laptops at once).

two hours is a long time to engage in any, even moderate, physical
activity.

it's best to think of this problem in these terms:  what is the ratio
of "usefulness time" to "charging time".  for the current laptop models,
that ratio is about 2 to 1 -- if you charge the laptop for 1 hour, it
will run for about 2 hours (very approximately).  this isn't a very
good ratio -- clearly 10 to 1 would be much better -- charge for an
hour, and get 10 hours of use, or, charge for just 12 minutes to get
the same 2 hours of use.  as noted below, we hope for 1.75 to be much
better (but probably still not 10 to 1).

paul


 > 
 > 
 > From: cjlhomeaddress at gmail.com
 > Date: Thu, 27 Oct 2011 14:29:19 -0400
 > Subject: Re: harvesting energy
 > To: tony_anderson at usa.net
 > CC: devel at lists.laptop.org
 > 
 > 
 > 
 > On Thu, Oct 27, 2011 at 2:14 PM, Tony Anderson <tony_anderson at usa.net> wrote:
 > 
 > 
 > Has anyone estimated the work required to charge an XO? Mike Lee gave a demo 
 > some time back at the Washington D.C. Learner's Club which seemed to show that 
 > it would be a difficult workload for an adult athlete to charge a laptop.
 > 
 > 
 > 
 > 
 > 
 > Tony
 > 
 > 
 > That equation will likely change substantially with the XO 1.75.
 > 
 > cjl 
 > 
 > 
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=---------------------
 paul fox, pgf at laptop.org