Limb etc. VS roof mount solar panel...... and the winner is?

Coachgeo

Explorer
Searched and could not find anything. If I missed something already discussed please point it out via a good search keyword to find it or a link.

That being said.... what do ya'll do to protect the solar panels from limbs etc on the roof of a Exp Rig? Very concerned about tree limbs etc. Why I ask is cause will be installing them onto an LMTV Expo Rig eventually and even though am keeping whole thing low as possible am still going to be taller than average truck.

In the end though they won't be on a roof per say as in typical set up but instead on a framework mounted on something more like a truck ladder rack. Anotherwords there will be an external roll cage around the bed of truck and camper box will slide inside and out of that. Cage stays mounted on bed and panels installed on it. Solar will stay on truck when camper removed . With that in mind do panels need to have their back to a flat surface for better strength?

For limb etc. protection am considered something like a layer of 1/2"? metal Hardware Cloth "X" number of inches above the panels. How much "X" should be not sure. Actually considering two layers with first being Concrete Wire Mesh base with the second smaller opening Metal Hardware Cloth above this. The Concrete Mesh would keep the smaller hardware cloth from flexing to far inward and scratching the panels when flexed inward via wind from driving or by limb pressing them down. Without the Concrete Mesh would think the Hardware cloth could flex inward too much thus requiring it to sit a good 8"? to a foot? above the panels. With the two layers could potentially be only inches above? Course then there is the nightmare of creating some way that the two meshes dont rattle like shiat against each other when driving.

Is 1/2" to big or small?

Is this whole idea wayyyy to overkill?

Open to suggestions.
 
Last edited:

rossvtaylor

Adventurer
Hi there,

If I understand your proposal correctly, you plan to put the mesh over the panels? This will absolutely kill your production... Even a narrow branch shadow, or a vent pipe shadow across a cell, or bird poop, can drop output considerably. I worked (after the fact, consulting) with a roadside installation of PV panels, put underneath a power line. Silly idea and just the shadow line cast by the overhead wire cut production to a small fraction. And your mesh proposal is, essentially, lots of interruptions to the circuit.

In our case, we're installing 3 large panels on top of a medium duty ambulance. But, there will be a 5-inch tall protective rack built around them. In the front, the cab rack and the box rack's front bars (angled down) will guide branches over the roof.

Don't, though, put mesh over the panels. Or you'll turn them into expensive overhead art.

Ross and Kara
 

dwh

Tail-End Charlie
No shade on any cells! Ever! Very bad! It will cut the voltage and when the voltage drops, it will be two low to charge a battery.

In other words...the solar will be useless. Any shade, even just a little shade on a couple of cells could be enough to drop the output down to a useless level.

And before you ask...no, even a clear protector like lexan is a bad idea:

http://2manytoyz.com/solarlexan.html

Protective railing is the only way unless you plan to remove the protective cover whenever you need the solar.
 

loonwheeler

Adventurer
Agreed that a protective railing is the way to go. Even if the railing just goes around the perimeter of the roof line and a couple of inches above the top of the panels can be enough for most protection needs. Every situation is different, but you do the best you can to protect them and a perimeter rail is a simple, easy, and cheap solution without casting shadows and killing your PV output.
 

Silverado08

Observer
No shade on any cells! Ever! Very bad! It will cut the voltage and when the voltage drops, it will be two low to charge a battery.

In other words...the solar will be useless. Any shade, even just a little shade on a couple of cells could be enough to drop the output down to a useless level.

And before you ask...no, even a clear protector like lexan is a bad idea:

http://2manytoyz.com/solarlexan.html

Protective railing is the only way unless you plan to remove the protective cover whenever you need the solar.

Wonder if that lexan sheet was larger and overlaped the panel bit more on all sides,,would the voltage still drop?
the way it creates shade is only from the edge of it,,not very acurate test imho..
 

dBeau

Hoopy
If I were really concerned about stuff hitting and breaking my panels, I'd go with a cover of some sort that would not transmit the full shock of an impact. Maybe a 1/4" plywood sheet with a bunch of 1/4" foam rubber spacers or the like. But then I don't expect my panels to do anything useful when driving. At camp, where there's no chance of impact, I'd just remove the cover and let the sun shine in. When driving, the alternator is going to do a far better job of charging then the panels, so who needs em? Keeping them covered while driving will also help to keep them clean. Dirty panels don't work very well.
 

Coachgeo

Explorer
... But then I don't expect my panels to do anything useful when driving. ....
Makes since and would be most logical route for 99% out there. For once I'm in the 1% hahah. In my set up I need/want it when driving as part power for Cab's AC. More power NOT produced by the Alternator the less strain on the engine, better fuel milage etc.
 

dwh

Tail-End Charlie
Wonder if that lexan sheet was larger and overlaped the panel bit more on all sides,,would the voltage still drop?
the way it creates shade is only from the edge of it,,not very acurate test imho..

Not optical glass and no anti reflective coating. Photons bounce off.
 

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