Plexiglass UV resistance

[Sunking]

I would completely agree but I think the question was more how good is plexiglass if you don't have the $$$ to spend.

Not worth a damn. There is no problem with yellowing of plexiglass despite what some claim. It will never be out in the sun that long.

The main problem is the first sunny warm day the plexiglass is going to expand and shatter all your solar cells leaving you with a pile of garbage. So tempered glass is much less expensive.

[carnini]

I wonder what the reasoning is behind every commercial panel company in the world using low Iron tempered glass is?
Increased snow and wind loading?
Lasts without scratching or yellowing for 25+ years?
Higher transmittance to light?
Lower thermal expansion rate?
Actually pretty difficult to break.
All of the above?

I would completely agree but I think the question was more how good is plexiglass if you don't have the $$$ to spend.

For example in my area, a piece of glass cut for a panel I recently made cost about the same if I choose tempered and low iron glass. I called around and everywhere within 50 miles had similar prices.

Plexiglass on the other hand around here is a ton cheaper, and readily find scrapes that can be used for good size panels.

Maybe that is more the question, if you are a diy starter, and want to give it a try without shelling out a lot of money, again might depend on where you live.

[Naptown]

I wonder what the reasoning is behind every commercial panel company in the world using low Iron tempered glass is?
Increased snow and wind loading?
Lasts without scratching or yellowing for 25+ years?
Higher transmittance to light?
Lower thermal expansion rate?
Actually pretty difficult to break.
All of the above?

[carnini]

ahhh, will have to think about that in my next build.
The concern about it expanding too much in the sun sounds like a very valid concern.
I know around here, tempered and low iron glass are almost the same price, for a custom cut piece, which is not cheap. Pleiglas on the other hand is much cheaper.

[chp]

Don't use plexi if you are going to encapsulate the cells. I was concerned about the plexi warping and used 1/4". It did not warp, but I didn't think about the expansion and contraction of the plexi in the sun. It basically ripped the cells apart. Next panel will be made with glass.

[carnini]

debating what to use

I am debating what to use also in my first build. I like the fact plexiglass, if it is uv resistant can be a bit easier to deal with.
Low iron glass is available too.
I do worry about if the glass is tempered and a tree limb hits it, will I detroy my entire panel vs plexiglass which will only leave a dent.

[poindexter]

glass by any other name???

Lots of folks are renovating around here in the toronto suburb area of ontario.. and throwing out their patio doors, these are 3 large glass panels.. each panel could make up about about 120 or 180 watt or more panels.
any thoughts on using these? or possibly shower doors??? with a Fur ply base?
I called the local lumber yard and they suggested that fur ply is great these days and reasonable, compared to marine ply. ( they sell the fur ply for sheds here without complaints).

[DeltaFox 25]

The 5x5 cell's I think is easy to work with and are not as brittle as the 6x6's . I have worked with the 3x6's and some 4x4's and I thought that these were very good also.

[Mike90250]

On the moisture issue Mike I think you can use a liquid sealer to seal the cells in place and then sandwich the cells in plexy

Feel free to do so.

[BuzzBuds]

As looking at the plexiglas it looks O K . I havn't measured the output for a long time , I'm changing the way I put the panels togeather and I'm making them biger , From 36 cell's to 72 cell's and I'm going with 5"x5" cell's from now on.

Just curious as to why the 5x5 cells what benifits do you get from them and are they 3 bus or 2 bus

[BuzzBuds]

Depends. Sometimes the glass cracks, and pebbleizes. (tempered glass does that) All the cracks shade the cells, and you loose 30% power. Then moisture gets in and rots the cells out.

Or, if the cells are bonded to the glass, they shatter too, and then the whole panel dies instantly.

All depends on how the panel gets broken - a baseball destroys the entire panel, a crack in a corner won't hurt much. Some examples attached

On the moisture issue Mike I think you can use a liquid sealer to seal the cells in place and then sandwich the cells in plexy

[DeltaFox 25]

I'll have to take some readings and put it on here. When I was new to the solar panel thing that is the only way I knew how to make a solar panel. I think the plexiglas was a little bit more money but I had at the time buy a hole sheet of the stuff and my glass company cut it for me. I now can cut it myself. That is all I had at the time.

[longwolf]

As looking at the plexiglas it looks O K . I havn't measured the output for a long time , I'm changing the way I put the panels togeather and I'm making them biger , From 36 cell's to 72 cell's and I'm going with 5"x5" cell's from now on.

I was just wondering if the power difference between the two justifies the extra expense for the tempered.

[DeltaFox 25]

As looking at the plexiglas it looks O K . I havn't measured the output for a long time , I'm changing the way I put the panels togeather and I'm making them biger , From 36 cell's to 72 cell's and I'm going with 5"x5" cell's from now on.

[longwolf]

...... I have one panel with Plexiglas ans two with low iron tempered glass and these seam to be holding up real good.........

Is your plexiglas still holding up well?
Have you measured the difference in output wattage's between the plex and the low iron panels?