Geoff Schultz wrote:
You can't produce more power
than the panels are generating.

Larry wrote:
Ok, here's a little electricity for everyone....

Geoff Schultz wrote:
Thank you Professor Larry for the edification. I always enjoy it when
this forum is used to exchange information instead of throwing barbs at
one another.

Goofball_star_dot_etal wrote:
Unfortunately the information is wrong.

Well without any references or explanation and as an anonymous poster,
your word isnt worth anything near as much as if it was printed out on
used toilet paper . .

If I didnt have concerns about RFI, I am capable of designing and
building my own MPPT solar panel controller. It isn't rocket science,
any competent EE tech or HAM operator (e.g. Larry) could knock one up in
a weekend or two, its just that it would take too much time so unless I
cant find something to do that brings in more beer tokens, its easier to
just buy one. Also it gives you someone *else* to yell at if it b***ers
up your reception on VHF channel 16.


For anyone else considering designing a MPPT controller (or just curious),
http://www.intusoft.com/nlhtm/nl78.htm
is good reading and even has Spice models for various types of solar
panel.

To summerise, they conclude that peak power is delivered at 83% of the
open circuit voltage (rather different from my estimate of 50% as I
initially was using an model that was an extremely bad approximation to
a solar cell. I should have googled :-( ), which varies with temperature
and illumination, and that a 10% gain in efficiency is achievable.

This means, if the controller is under 10% of the panel cost, buy it,
its a no-brainer, otherwise get a bigger panel (gross
over-simplification ignoring cost of a liniar regulator, assuming you
CAN fit a bigger panel (or more), you need more power and assuming
price/performance for the panel is a streight line.)

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL:
'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed,
All varnished hot moulded wooden racing dinghy.