Larry wrote in
:

BruceinBangkok wrote in
:

I was asking about the preferred type of regulator, i.e., shunt,
open- close circuit, short circuit.

If you look at the cells on a heavily loaded panel, notice how brown
they get overheating in the noonday sun so quickly? That should
answer your above question. ANYTHING you can do, like DISCONNECT
(read that series open circuit regulators) an unneeded solar panel in
the hot hot sun to GET THE CELL TEMPERATURE DOWN is always a GOOD
thing. The way to get the heat down is to LOWER, not raise, the cell
current. That part of the cells that don't have any current going
through them never seems to change from that blue silicon color to
that brown, scorched-earth look. It's the CURRENT that fries them.
Shunt regulators simply drive up the cell current, which drives up the
cell HEATING until the cell fails....making the cell salesmen simply
smile. Shunt regulators are for suckers.....

My own boat has three panels charging a medium size bank and never
gets above 13.5 V. On the other hand it will only run a DC fridge if
the sun shines all day, every day.
Cheers,


If you can still get a sun tan on a 40' boat who's charging is solar
panels running a fridge with no wind charger....the fridge will easily
keep the cells from overcharging the battery. It's really hard to
develop enough power to fry a LOADED battery with solar cells.
BUT...NEVER LEAVE THE BOAT BATTERIES CONNECTED TO SOLAR PANELS WITHOUT
A LOAD!....that'll fry it over a week.

All solar chargers on boats seem to suck....about like those boat fans
buzzing away over your bunk....cheap crap. But, I'd never use a shunt
controller as it fries the cells in a hot sun at low latitudes. They
all turn BROWN where the current flows!

I've never seen a solar cell fried in the sun unloaded......even in
the Iranian desert mountains.

I must be confused by what you wrote. You're stating that solar cells
turn brown if they're loaded?!? What solar arrays have you seen that
aren't loaded? And if so, why where they installed? I've rarely seen a
case where the entire output of an array hasn't been needed/used other
than when a boat was at dock.

Personally I use a diversion controller since it handles both my wind
generator and solar panels and the wind generator has to have a load to
keep it from free-wheeling.

I've been very happy with my Morningstar Tri-star controller, but have
nothing but bad experiences with Xantrex C-40 controllers.

-- Geoff
www.GeoffSchultz.org