Once I mounted my panels on top of my radar arch, I realize that I couldn't
see the sea gull $hit on them and now it's just a routine to check them
every day or so with a wet towel.

My ultimate solution was to add a wind generator to over come this problem
and the lack of sun here in the PAC NW.. Beside out sun angles average to be
too low for efficient solar here..

If you have a specific objective in solar requirements, then the solution
may be to add more solar area.

Steve
s/v Good Intentions

Look at the websites for the various manufacturers. The popular
ones are Siemens, Kyocera, BP, Sharp. They describe the
features of their products. Shading effects are covered.

Doug

"bert" wrote in message
...
So how do I know which ones to buy ?

On Wed, 3 Mar 2004 16:46:22 -0500, "Doug Dotson"
wrote:

That's old technology. The newer panels are not nearly as
sensitive to minor partial shading. I've never seen any specs
that describe this affect in a quantitative manner.

Doug
s/v Callista

"Steve" wrote in message
...
I believe the problem you discribe is common to most all commonly used
panels. Any shadow across the cells will cut off or diminish the output
of
the cells in that region.

Yes, even a rigging or halyard can effect the output.. The whole
problem
stems for the fract that the cells or groups of cells are wired in
series
and if you have reduced output from one cell the remainder in that
group
will be effected..

Kinda like having a bad NiCad cell in a battery pack or a bad cell in a
lead
acid battery..

I have been using a pair of Solrex VLX 53s for ten years and I just
learn
to live with this problem. On my current boat I have them on my radar
arch
and that seems to have eleminated most of the shadow problem. However,
now
that I have added a wind generator, I now have problem with the prop
casting
a shadow on the panels.. Not to bad if it is spinning.

Steve
s/v Good Intentions

Look at the websites for the various manufacturers. The popular
ones are Siemens, Kyocera, BP, Sharp. They describe the
features of their products. Shading effects are covered.

Doug

"bert" wrote in message
...
So how do I know which ones to buy ?

On Wed, 3 Mar 2004 16:46:22 -0500, "Doug Dotson"
wrote:

That's old technology. The newer panels are not nearly as
sensitive to minor partial shading. I've never seen any specs
that describe this affect in a quantitative manner.

Doug
s/v Callista

"Steve" wrote in message
...
I believe the problem you discribe is common to most all commonly used
panels. Any shadow across the cells will cut off or diminish the output
of
the cells in that region.

Yes, even a rigging or halyard can effect the output.. The whole
problem
stems for the fract that the cells or groups of cells are wired in
series
and if you have reduced output from one cell the remainder in that
group
will be effected..

Kinda like having a bad NiCad cell in a battery pack or a bad cell in a
lead
acid battery..

I have been using a pair of Solrex VLX 53s for ten years and I just
learn
to live with this problem. On my current boat I have them on my radar
arch
and that seems to have eleminated most of the shadow problem. However,
now
that I have added a wind generator, I now have problem with the prop
casting
a shadow on the panels.. Not to bad if it is spinning.

Steve
s/v Good Intentions

x-no-archive:yes "Lloyd Sumpter" wrote:

On Wed, 03 Mar 2004 09:46:57 +0000, Steve wrote:

I believe the problem you discribe is common to most all commonly used panels.
Any shadow across the cells will cut off or diminish the output of the cells in
that region.

Yes, even a rigging or halyard can effect the output.. The whole problem stems
for the fract that the cells or groups of cells are wired in series and if you
have reduced output from one cell the remainder in that group will be effected..


That's why I've never mounted mine. It's just a loose panel, so I'm free to
place it wherever there is max sun and min shade. Takes a little "hands-on", but
works good. (and haven't lost it overboard in 5 years!)


We actually did lose one overboard that was on the dinghy davits - the
brace between the davits worked free in a heavy sea. (We didn't get
pooped - it was just the dinghy swinging with the (very small 3.5
horse) motor on it. I've also heard of folks having ones mounted on
the lifelines who've had a problem with losing them.

Actually I've not seen that the problem of shadows was all that bad.
We even get a little activity from the moon or from marina lighting.

Some folks we know have a bank of panels on the radar arch on the
stern that will tilt forward and aft according to the angle of the
sun. Right now we have 2 on the foredeck beside the staysail boom
propped up to take advantage of the prevailing sun here.

The wind generator next to the panel on the radar arch seems to keep
birds from sitting on the panel there. Pelican's particularly almost
never land on our boat if there are others available.


grandma Rosalie