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.

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

Geoff Schultz wrote in
:

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.



Wind generators need shunt controllers to keep them from freewheeling
and throwing the blades off. We're talking, here, about SOLAR PANELS
and I'll stick to that.

Any solid state device, including solar panels, have one enemy, HEAT!
They fry from the heat. This causes doping migration across the
junction. A solar panel is simply a 2-pole diode exposed so photons can
drive electrons across the junction. It's why you always have a
blocking diode because it will conduct like a diode the other way
discharging the battery at night or in clouds.

Heat cooking common solar panels is easily seen in the area of each cell
where the current flows through the device, leaving the area around the
edges where no current flows its original metallic blue color. The
current area of the cell gets browner and browner as it ages and the
heat causes the cell's fundamental chemistry to change, lowering output.
Look at any old solar panel that's been pumping out the amps for a few
years and you can see it.

Now, the batteries are charged and the solar array in the hot noonday
sun is attempting to crank out its 19V open circuit voltage. The common
shunt regulator simply loads down the solar cell with a shunt resistance
to cause the array's inherent series resistance to absorb the difference
between the array's open circuit voltage, around 19V and the desired
float voltage of 14.2V for 12V lead-acid house batteries. Let's do some
simple math...19 - 14.2 = 4.8 volts dropped inside the series of cells x
whatever total current the array is cranking out in the hot, direct sun
say 10A for simplicity = 48 WATTS of heat MORE than what the natural no-
current temperature rise of the panels is with no load current. 48
watts is a fairly good amount of heat when concentrated in that little
circle that's turning brown in the middle of the cells. Don't think so?
Try this. take a contact thermometer or an infrared thermometer that
can measure the temp of the cells UNPLUGGED in that hot sun. Now, plug
it into the combination of shunt controller/battery in its normal
connection. Watch the temperature of the cells rise with that 48W of
heat across the panels. It's a serious amount. Leave that running a
few years at 6-7 hours on sunny days.

Why go to all that when it's SO easy to put in a SERIES controller that
will simply SWITCH OFF the power at 14.2V and switch it back on, again,
at 13.2V just like a good battery charger? Why make the cells so HOT?!
Unlike the windcharger which NEEDS the load current to slow it down from
overspeed....solar cells DON'T!

http://www.solazone.com.au/Regulators.htm
Why not install a multistage series regulator that charges up the house
batteries EXACTLY like your multistage AC charger does?

http://www.arrid.com.au/?act=Solar%20Regulators

http://www.marinewarehouse.net/blueskyenergy.html

http://www.wirefreedirect.com/mornin...ontrollers.asp
"These products are well known for their reliability and ability to
extend battery life and capacity through their PWM - Pulse Width
Modulation technology - the battery is continually poled (pulsed) so
maintaining the battery in a fully topped up state and ensures the
voltage remains constant. This method ensures that the battery
receives maximum charge, whilst preventing overcharging. The
Morningstar range range of solar controllers charge controllers are
famous for their superior quality of construction reliability. "

Constant voltage, PULSED charging....just like your AC charger at the
dock.

Larry wrote in
:

Geoff Schultz wrote in
:

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.



Wind generators need shunt controllers to keep them from freewheeling
and throwing the blades off. We're talking, here, about SOLAR PANELS
and I'll stick to that.

Any solid state device, including solar panels, have one enemy, HEAT!
They fry from the heat. This causes doping migration across the
junction. A solar panel is simply a 2-pole diode exposed so photons
can drive electrons across the junction. It's why you always have a
blocking diode because it will conduct like a diode the other way
discharging the battery at night or in clouds.

Heat cooking common solar panels is easily seen in the area of each
cell where the current flows through the device, leaving the area
around the edges where no current flows its original metallic blue
color. The current area of the cell gets browner and browner as it
ages and the heat causes the cell's fundamental chemistry to change,
lowering output. Look at any old solar panel that's been pumping out
the amps for a few years and you can see it.

Now, the batteries are charged and the solar array in the hot noonday
sun is attempting to crank out its 19V open circuit voltage. The
common shunt regulator simply loads down the solar cell with a shunt
resistance to cause the array's inherent series resistance to absorb
the difference between the array's open circuit voltage, around 19V
and the desired float voltage of 14.2V for 12V lead-acid house
batteries. Let's do some simple math...19 - 14.2 = 4.8 volts dropped
inside the series of cells x whatever total current the array is
cranking out in the hot, direct sun say 10A for simplicity = 48 WATTS
of heat MORE than what the natural no- current temperature rise of the
panels is with no load current. 48 watts is a fairly good amount of
heat when concentrated in that little circle that's turning brown in
the middle of the cells. Don't think so? Try this. take a contact
thermometer or an infrared thermometer that can measure the temp of
the cells UNPLUGGED in that hot sun. Now, plug it into the
combination of shunt controller/battery in its normal connection.
Watch the temperature of the cells rise with that 48W of heat across
the panels. It's a serious amount. Leave that running a few years at
6-7 hours on sunny days.

Why go to all that when it's SO easy to put in a SERIES controller
that will simply SWITCH OFF the power at 14.2V and switch it back on,
again, at 13.2V just like a good battery charger? Why make the cells
so HOT?! Unlike the windcharger which NEEDS the load current to slow
it down from overspeed....solar cells DON'T!

http://www.solazone.com.au/Regulators.htm
Why not install a multistage series regulator that charges up the
house batteries EXACTLY like your multistage AC charger does?

http://www.arrid.com.au/?act=Solar%20Regulators

http://www.marinewarehouse.net/blueskyenergy.html

http://www.wirefreedirect.com/mornin...ontrollers.asp
"These products are well known for their reliability and ability to
extend battery life and capacity through their PWM - Pulse Width
Modulation technology - the battery is continually poled (pulsed) so
maintaining the battery in a fully topped up state and ensures the
voltage remains constant. This method ensures that the battery
receives maximum charge, whilst preventing overcharging. The
Morningstar range range of solar controllers charge controllers are
famous for their superior quality of construction reliability. "

Constant voltage, PULSED charging....just like your AC charger at the
dock.

I understand how the various types of regulators work. What amazed me
was your statement about utilizing a type of regulator to avoid placing a
load on the solar cells to keep them from turning brown.

You've spent too much time at a dock if you think that's a problem for a
cruising boat or any household system, as the demands typically outstrip
generated supply and you're sucking every watt that the panels can make.
If you're not using them, why waste the money installing them?

For me, my panels get disconnected when I pull into dock for extended
stays, and for short stays the excess power goes to heating water, so I'm
being "green."

-- Geoff
www.GeoffSchultz.org

On Tue, 27 Jan 2009 22:11:33 +0000, Larry wrote in
:

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.....
...
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.

Turning brown is caused by UV, weathering and environmental heat, not
heating from load, and has a relatively small effect on power output (on
the order of 5-10%). See:
* http://www.freepatentsonline.com/6114046.html
* http://www.faqs.org/patents/app/20080276983
* http://www.wipo.int/pctdb/en/wo.jsp?...A=WO2005006451
* http://www.patentstorm.us/patents/54...scription.html
More modern cells are more resistant to this kind of discoloration.
Keeping the cell under load isn't an issue.

--
Best regards,
John Navas, publisher of Navas' Sailing & Racing in
the San Francisco Bay Area http://sail.navas.us/

John Navas wrote in
:

Turning brown is caused by UV, weathering and environmental heat, not
heating from load, and has a relatively small effect on power output (on
the order of 5-10%). See:


If that were true, each whole cell would turn brown, not just the center of
the cells where the conductors are directing the current through it. The
current through the cell resistance adds a lot of heat to a cell generating
power.

Case in point, there are solar panels all along our local interstate now
over 10 years old. They are lightly loaded for their size only generating
enough power to charge some gelcells and power the roadside webcam and its
upload server. The cells have not discolored from 10 years in the HOT
South Carolina sun that I can detect.....as they have low current in them
except for in the first morning light until the gelcells recharge from
running the cam all night in the dark.

The panel on Lionheart is 1988 and is nowhere near a charger for the
massive monster house batteries banks' 1400 AH and loads. It spends all
its time completely saturated. The part of the cells where the heavy
current goes through them has turned them all a very light brown so you can
hardly recognize them as solar cells any more. They still generate a few
amps like that but nowhere near what they should.

Cap'n bought a new panel to replace it. But, alas, he didn't have time to
install it and forgot the panel was laying on top of the old panel when his
guests showed up for a harbor cruise. He forgot the new panel, a really
nice one, was loose. When the boat heeled, the new panel slid over the
side into the harbor mud in 50' of channel. It's best not to mention
replacing the old solar panel, even today. If you mention it, make sure
you do so as you're stepping onto the dock for the last time headed home
for a couple of weeks.....(c;]

Glad it wasn't me involved in that one.....

On Sun, 01 Feb 2009 21:30:21 +0000, Larry wrote in
:

John Navas wrote in
:

Turning brown is caused by UV, weathering and environmental heat, not
heating from load, and has a relatively small effect on power output (on
the order of 5-10%). See:


If that were true, [SNIP]

It is true, as shown by my supporting citations.

Typical solar panels convert only about 20% of captured solar energy
into electricity. The other 80% is wasted as heat. Thus if even half
the power of the solar cell were converted into additional heat, it
would only increase heating by about 12% (10 ÷ 80), which isn't terribly
significant.

If you have any real evidence (citations) to the contrary, then by all
means post it.

--
Best regards,
John Navas, publisher of Navas' Sailing & Racing in
the San Francisco Bay Area http://sail.navas.us/

John Navas wrote:
On Sun, 01 Feb 2009 21:30:21 +0000, Larry wrote in
:

John Navas wrote in
:

Turning brown is caused by UV, weathering and environmental heat, not
heating from load, and has a relatively small effect on power output (on
the order of 5-10%). See:

If that were true, [SNIP]

It is true, as shown by my supporting citations.

Typical solar panels convert only about 20% of captured solar energy
into electricity. The other 80% is wasted as heat. Thus if even half
the power of the solar cell were converted into additional heat, it
would only increase heating by about 12% (10 ÷ 80), which isn't terribly
significant.

If you have any real evidence (citations) to the contrary, then by all
means post it.

The funny thing is, that a loaded solar array is cooler than
an unloaded one.
The unloaded one absorbs heat, the loaded one less, because you
convert to electricity, and use it.
So by loading it , you remove heat.
Not all of it, because part of the energy is lost as heat.