Mostly it's all about the frame. A PV module (solar panel) is nothing but very thin wafers of silicon bonded to tempered glass and then vacuum sealed with a resin or epoxy backing. Then they take that and mount it in a frame.
For big architectural projects, the contractor might buy the modules with no frame because they are going to mount them with their own frame design as part of the building.
Some manufacturers offer the same PV modules mounted in different frames.
The frames are usually just aluminum channel, but there are some modules with beefy frames and some with sort of cheezy frames.
There are some modules where the silicon wafers are bonded to lexan or some other plastic instead of glass, and have plastic frames. I guess these have a little bit of flex to them, but it can't be much since the silicon wafers absolutely will crack if flexed.
There are also "thin film" modules, which are flexible, but not as efficient and probably not as long lasting.
A module made with tempered glass and mounted in a solid frame should hold up well. They are actually fairly tough and have regularly withstood golf ball sized hail. Just don't bend or twist them.
Personally, I wouldn't trust any aluminum channel frame to provide enough support for serious off-roading. I would build a stong frame to mount them to.
EDIT: If you look at the picture above, you can see that those modules are mounted in some nice hefty frames.
EDIT2: Another thing, if you look at that picture, you can see that the mounting tabs are positioned at the ends of the frames. Obviously, that could allow the centers to flex a bit (if the frames weren't as heavy as they are). In mounting modules on buildings, to withstand the greatest wind and/or snow and ice load, the mountings are generally not at the ends of the modules, they are usually about 1/4 to 1/3 in from either end. That keeps the flexible span as short as possible.
Last edited by dwh; 12-08-2010 at 11:10 PM.
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