[Peripherals] electricity table (Google Docs)

[John Watlington]

Please don't use information from Potenco, there are too many  
complications
with their design.   They assume that the battery being charged can  
accept
all the power their device outputs.

If using the crank from Freeplay, It can charge the laptop at 17W  
(given the
user is willing to crank fast).

John

On Jul 18, 2008, at 9:09 PM, Edward Cherlin wrote:

> 2008/7/18  <mianeil2 at yahoo.com>:
>> I've shared a document with you called "electricity table":
>> http://spreadsheets.google.com/ccc?key=p6DRYWvC0_wbHL1- 
>> bzt-3Mw&inv=devel at lists.laptop.org&t=808765302247483981&guest
>>
>> It's not an attachment -- it's stored online at Google Docs. To  
>> open this
>> document, just click the link above.
>>
>> Hi guys!
>> I was also wondering if you could give me feedback on this table. The
>> table shows how much kWh is needed a year to power a xo based on
>> different scenarios. If you think I should add or change anything
>> please let me know.
>> Thanks a lot!
>> Mia
>
> I don't understand your calculations. Your table labels the power
> column in kWh, which is the wrong unit. It should be W, so that you
> get Wh when multiplying by hours. Thus, for example, if we have 6 W (
> roughly the power used by a single XO) for 5 hours a day for 365 days
> annually, it comes to 10950 Wh or 10.9 kWh.
>
> You also don't give a formula for power generation time. The Potenco
> site gives this information:
>
> A minute of pulling the PCG generates enough energy for:
>
>     * 20 minutes of talk time on a mobile phone
>     * 1 hour of ultrabright LED flashlight use
>     * 3 hours play time on an iPod Shuffle (about one pull per song)
>
> If one minute of pulling gives one hour of use, this comes to 5
> minutes a day in the case I considered above, and similarly for the
> other possibilities given, from 2 minutes to 15 minutes daily. Your
> table, unaccountably, gives well over an hour of pulling daily.
>
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>
>
>
> -- 
> Edward Cherlin
> End Poverty at a Profit by teaching children business
> http://www.EarthTreasury.org/
> "The best way to predict the future is to invent it."--Alan Kay
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