[Peripherals] CIS solar charging-correct list?

[scott at gnuveau.net]

Hi Stan,

On Thu, 31 Jul 2008, Stan. SWAN wrote:

> Scott: Thanks for this solar net one info, which (as an electronic
> guru) impresses me.

Thanks.  We have been refining it a bit also.

> Are those PV arrays 600 Watts?? Yikes- allow
> ~US$3k for these alone (about the annual salary for a teacher in many
> downtrodden areas). Double this for the battery bank!


Its a little less than that.  The array and battery bank are enough for
6-7 user seats and a VSAT terminal 24/7, plus the long range wifi, which
will be central to building any ISP type services out.  To date, most of
the systems have been subsidized by non-profits for placement in
developing nations.  You are still looking at
a higher cost with multiple power sources, and a way higher cost with
building a standard power grid.  The first hurdle to be overcome is power
supply.  This is impossible with PC's, as you are probably aware, due to
the cost of the power system.  OLPC is a good solution for this.  We use
geodes in the SolarNet thin clients... very efficient.

The second challenge is connectivity.  The mesh is pretty good for this
too, once there is an upstream circuit somewhere within range of the
mesh.  In many places, this will be VSAT or long range wifi hops.
The backbone has to start somewhere...

> Maintenance?

Distilled water in the batteries, with an option for maintenence free
batteries.  The latter just cost more per wH of storage.
Notwithstanding, much better than the maintenence on a standard diesel
generator, which is the power source of choice in western Africa.

>
> IMHO such a solar scheme is pipe dream stuff for subsistence lifestyle
> regions that can hardly stretch to a litre of kerosine for lights,

Solomans?

http://self.org/solomonislands.shtml

These things are possible, just not as a simple capital exchange.

> &
> even just a single one may be orders of magnitude more costly than
> schools & villages in the PNG/Solomon Islands region can justify...

I know it seems pricy... its new.  Component cost will go down over time,
but one has to remember that when buying solar panels, one is buying 20
years worth of electricity up front.

The point was that I have put quite a bit of effort into R&D on rural
power systems for networks, and if any of that knowledge would be helpful,
I am happy to provide it.  I think you will likely be better off with a
single large central "charging station" in the school than individual
panels for each OLPC.

Cheers,
Scott

> Stan in NZ
>