Solar panel mounted behind window

[hammick]

I have an off grid barn with two South facing 42" x 30" awning windows. I can remove the screens.

Any reason I can't mount a 100w panel right up against the window? Does the argon in the glass cause any issues?

These panels will only be used for trickle charging 12v batteries during the winter. I really don't want to mount these panels on the roof or walls (I will have plenty of big panels on the roof when my 48v system is installed).

Thanks for any advice.

[inetdog]

I have an off grid barn in Montana with two South facing 42" x 30" awning windows. I can remove the screens.

Any reason I can't mount a 100w panel right up against the window? Does the argon in the glass cause any issues?

These panels will only be used for trickle charging 12v batteries during the winter. I really don't want to mount these panels on the roof or walls (I will have plenty of big panels on the roof when my 48v system is installed).

Thanks for any advice.

There are a lot of problems with that approach. Among them are:

1. Up against the glass, unless its a skylight, will not aim the panel properly toward the sun when it is above the horizon. You can see this alignment loss by plotting different horizontal angles in PVWatts.
2. When the sun is above the horizon there will be reflection of incoming light at all of the surfaces of the window, costing you power.
3. The glass, particularly if it is a low-E window design, will block much of the light in the frequency range that the panels need to operate.

There's more, but that should be good start.

The saving grace for your application is that you can afford to buy a 50W panel and only expect to get 10W out of it and still be able to use it as a battery maintainer.

[hammick]

I know the 90 degree angle will not be correct. I can probably angle them some.

I purchased two of these panels primarily because the dimensions fit my windows and the price was right.

They will only be used behind the windows in the winter. During the summer I'll probably build a portable mount for them and put them outside at the correct angle.

I'll report back in a few weeks how they worked behind the windows. Thanks.

[J.P.M.]

In Montana (or anywhere else), the windows will admit much more energy to heat the dwelling in the winter than equally sized solar panels will generate. Not a cost effective idea. Not real good for the view either.

[inetdog]

These are windows on an un-insulated garage. Sole purpose will be float charging when garage is vacant. This is a vacation place and I live 1,100 miles away. My goal is to leave batteries in garage so I don't have to haul them back and forth.

That is possible. Just do not count on getting anywhere near full power from the panels.

And if you get snow on the ground then vertical orientation may get more light on the panel than the nominal best orientation.

[Wy_White_Wolf]

Hang the panel on the outside wall of the barn and make the mount adjustable. Hanging vertical in the winter will be close enough for full power and help to keep the snow cleared off. My mount that I put on a storage shed made from old bed frames.





WWW

[inetdog]

I suspect that the OP is concerned about theft as well as environmental damage.

[inetdog]

I guess the Argon in windows really works.

The argon in the windows is part of the thermal insulation, and should have no effect one way or the other on the light absorption and reflection characteristics.
Low-E glass is significant though.

[hammick]

The argon in the windows is part of the thermal insulation, and should have no effect one way or the other on the light absorption and reflection characteristics.
Low-E glass is significant though.

OK. They are nice windows with good Low-E specs.