On 10/28/2011 10:10 PM, Hal Murray wrote:
I haven't carefully checked the accuracy of my Kill-a-Watt, but it's passed
all my sanity checks. At $20, it's a useful tool. (The technology for this
sort of thing must be reasonably solid. My new electric meter has an LCD
rather than a spinning whee
On 10/27/2011 11:45 PM, Richard A. Smith wrote:
In this specific case the question was about human power so its
reasonable to assume that the setup would use a direct DC input.
Otherwise you are losing 30% or more of your power in conversion losses.
The number I use for the DC input is 25 watt-
> Good point. Thanks. It's even worse than that. In the power mode, the
> Kill-a-Watt only shows whole watts, no fraction.
It's worse than that. IIRC mine only shows 6, 12, or 18 watts at that
low a value. Useless for really low power. I ended up using a test
board for a switching power su
rich...@laptop.org said:
> Speaking from experience measuring the power draw of a single XO with these
> low cost power meters is tricky. They can be very inaccurate at lower
> power measurements. The kill-a-watt for example has a typical accuracy of
> 1% with a max of 4%. Full scale is 1800
On 10/27/2011 11:45 PM, Richard A. Smith wrote:
Is the XO running or powered off?
Is it for a XO-1.5 or XO-1.5?
Oops. XO-1 or XO-1.5
--
Richard A. Smith
One Laptop per Child
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arge 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: cjlhomeaddr...@gmail.com
> > Date: Thu, 27 Oct 2011 14:29:19 -0400
>
Wow! De ja vu! I think I asked some of the exact same questions ages
ago here and have been discussing the exact same harvesting methods
with friends when hanging out:)
I think the biggest problem about these are currently cost and
fragility/durability.
The recess/lunch/playtime thing and strappi
o be much
better (but probably still not 10 to 1).
paul
>
>
> From: cjlhomeaddr...@gmail.com
> Date: Thu, 27 Oct 2011 14:29:19 -0400
> Subject: Re: harvesting energy
> To: tony_ander...@usa.net
> CC: devel@lists.laptop.org
>
>
>
> On Thu, Oct 2
> Due to our battery-management system, it is impossible to charge an
> XO laptop in less than about 110 minutes.
Are humans better at shorter bursts of higher power? Perhaps a
human-powered charging system would benefit from some intermediary
storage, either electrical or mechanical - supercaps
gt;> devel-ow...@lists.laptop.org
>>
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>> Today's Topics:
>>
>>1. Re: harvesting energy (Chris Leonard)
On Thu, Oct 27, 2011 at 2:14 PM, Tony Anderson 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.
>
> To
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Today's Topics:
1. Re: ha
On Thu, Oct 27, 2011 at 7:23 AM, Kristen Eisenberg <
kristen.eisenb...@yahoo.com> wrote:
> If we're talking about kids powering their own devices, I think the
> way to go is to turn "work" into play. The merry go round/hard bar
> swing would fit in this category.
>
> So basically, let's look at ac
On 10/27/2011 05:23 AM, Kristen Eisenberg wrote:
If we're talking about kids powering their own devices, I think the
way to go is to turn "work" into play. The merry go round/hard bar
swing would fit in this category.
So basically, let's look at activities where energy exerted is ambient
anyway?
If we're talking about kids powering their own devices, I think the
way to go is to turn "work" into play. The merry go round/hard bar
swing would fit in this category.
So basically, let's look at activities where energy exerted is ambient
anyway? What I mean is that the energy is being used up by
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