[Its.an.education.project] Ivan's latest blog entry on OLPC

[John Watlington]

On May 17, 2008, at 9:14 PM, Jim Gettys wrote:

> On Sun, 2008-05-18 at 10:32 +1000, Martin Sevior wrote:
>> HI Jim,
>>          Your answer didn't actually appear here.
>>
>> Alan, there are *LOT* of research groups and companies who say they
>> have the technology to produce cheap solar cells, or will do if they
>> "could just get a bit more funding", I was under the impression that
>> OLPC had found a Chinese company that was actually delivering  
>> flexible
>> panels at $2.50 per watt.
>>
>
> Sorry, slip of the finger....
>
> Gold Peak.  We're trying to get the supply chain moving...  I don't  
> know
> the individual prices.
>                      - Jim

It is their subsidiary, GP Solar.
However, the $2.50/W price was specific to OLPC and last year.  Due to
increases in raw materials cost, it was heading upwards last time I  
asked.
This is for amorphous silicon solar panels, but they at least absorb  
on more
than one frequency, improving the size/W.

To the person using car batteries for storage --- bad idea, due to  
cost over lifetime,
and maintenance requirements.   Once you factor in everything, a  
higher priced
battery up-front may still lead to a lower cost of operation over  
five years.   We are
pursuing LiFePO batteries with GP.  The alternative is the AGM or gel  
lead batteries
(still slightly cheaper) but they aren't so good for the environment...

You also underestimated the battery capacity required (this is an  
area for
lots of discussion!)    Do you want to run a single school server for  
eight hours
a day, with two days of reserve capacity ?   Or do you want to  
provide a system
that will provide power for 30 students and a server (24/7), w. one  
day reserve ?
In most reasonable cases, you are talking multiple K$ for the storage  
subsystem.
This makes water powered systems (which should be feasible in Peru) more
attractive, as the battery acts mainly as a UPS in those cases.

The OLPC Multi-battery charger provides the electronics and mechanicals
necessary to connect up to 15 batteries up to a 12VDC (or 90-240VAC)  
supply.
We designed it to minimize the amount of intermediate storage --- you  
charge laptop
batteries directly when the sun is shining, instead of charging a  
lead battery
then using it to charge laptop batteries.   But even this approach  
requires additional
laptop batteries...

Cheers,
wad