On Wed, 10 Jul 2002, Richards, Justin P wrote:

>What I had in mind was to use a separate solar panel and small inexpensive
>regulator  for each battery.  This eliminates the dc/dc upconverter.  This
>sounds expensive using 20 regulators, 20 solar panels and 20 batteries (at
>12v),  but the regulators are all low power and second hand 33 watt panels
>are cheap.  Smaller batteries are easier to handle and if one fails it is
>not a huge loss.

It isn't just that, you can buy bulk surplus stuff and save serious $$$.
Also if something breaks you can quickly swap a module and fix it. You
can't do that with a large turnkey installation. Just do some real good
thinking on connections and layout. You will have a large number of
interconnects and failsafe systems and such, and you need to think a bit
about how to do this right. I'd think about honking big screw-clamp rows
mounted on a custom-built rack to hold the whole installation, with short
wires connecting the identical modules up front. The batteries and dc/dc
converters would be on the shelves of the rack. 20 batteries will weigh
towards a ton so spend some time on mechanical construction and such.
Breakers and such I would put on rails screwed to same rack. The rack
should be solid but non-combustible and insulating. Fire retardant treated
wood might work. Charge equalization is a must. If the dc/dc converters
are not insulating then the solar panels will float at high voltage. You
can't have that, thus use insulated dc/dc converters. They are not so hard
to get, esp. at 30W.

Peter

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