Solar Panel Selection/Fit Help

[Ford_6L_E350]

Why can't a solar panel hang over the sides of the top? No reason it has to be narrower than the space under it.

Mike

[daveb]

Originally Posted by Ford_6L_E350

Why can't a solar panel hang over the sides of the top? No reason it has to be narrower than the space under it.

Mike

Probably depends on the terrain you visit. I'd be very worried unless I had some kind of rack bar protecting something hanging over the edge...but I'm rough on my rig and tend to crash through trees. At least the Aluminess rack mine are mounted in does a good job protecting my panels. I still worry about pinecones and one panel only lasted about 2 weeks when the K-40 antenna smacked it...BTW, wasn't it you Mike that pointed out it was busted ?

[jage]

Again, what is the theory on partial shade/shadow on a panel? I've heard that thrown around as a no-no but don't understand the effect is.

[daveb]

Originally Posted by jage

Again, what is the theory on partial shade/shadow on a panel? I've heard that thrown around as a no-no but don't understand the effect is.

I was told it depends on how the shadow hits the panel. This might help but I don’t know if more modern or different type panels react differently to shadow.

If even a small section of a photovoltaic panel is shaded - for example by the branch of a tree - there is a very significant drop in power output from the panel. This is because a PV solar panel is made up of a string of individual solar cells connected in series with one another. The current output from the whole panel is limited to that passing through the weakest link cell. If one cell (out of for example 36 in a panel) is completely shaded, the power output from the panel will fall to zero. If one cell is 50% shaded, then the power output from the whole panel will fall by 50% - a very significant drop for such a small area of shading.

[cygvan]

ive read that some pv panels come with blocking diodes which minimize this effect to some degree but its still wize to avoid shading.

[Ford_6L_E350]

Yes, Dave it was me who gave you the bad news.

But, not everyone goes places you go. For most of us, a solar panel hanging over the side of the penthouse roof a few inches is not a big deal - especially if it is on the side that already has an awning.

Mike

[sdwindansea]

I'm leaning on not worrying too much about a couple of inch overhang on the side as Mike suggested. Especially since it will not be wider than the van body itself.

I'm planning on buying the Kyocera KD135SX-UPU (http://www.solar-electric.com/kykc130wasop.html). This is the one with the junction box, not the MC4 connector cables. Am I correct in going with this version over the MC4 connection?

Also, do you know if I will need to supply SMB with the mounting hardware and other cabling or will they be able to handle it?

Thanks again for all of the help.

[daveb]

Originally Posted by cygvan

ive read that some pv panels come with blocking diodes which minimize this effect to some degree but its still wize to avoid shading.

Yes and some panels use light diffusers to minimize the effect. You’ll see both of these in many of the marine panels that have to deal with shadowing from sails and rigging. The Solara panels were designed that way. Like I posted, I’m not sure about each manufacture. I went with Kyrocera because SMB was using them, they carry a warrantee for RV use, and the rack that Aluminess made was designed around that size panel (135w).

Originally Posted by Ford_6L_E350

Yes, Dave it was me who gave you the bad news.

But, not everyone goes places you go. For most of us, a solar panel hanging over the side of the penthouse roof a few inches is not a big deal - especially if it is on the side that already has an awning.

Mike

Yes but it’s still an issue and worth looking for an alternative if a good one is indeed out there. Hail, pinecones and rocks are still a concern for me even though I got rid of the K-40 antenna.

Originally Posted by sdwindansea

I'm leaning on not worrying too much about a couple of inch overhang on the side as Mike suggested. Especially since it will not be wider than the van body itself.

I'm planning on buying the Kyocera KD135SX-UPU (http://www.solar-electric.com/kykc130wasop.html). This is the one with the junction box, not the MC4 connector cables. Am I correct in going with this version over the MC4 connection?

Also, do you know if I will need to supply SMB with the mounting hardware and other cabling or will they be able to handle it?

Thanks again for all of the help.

I’m running 2 of those and I bought the one I broke from those guys. SMB was surprised of the low cost. I know SMB has a few ways to mount the panels. They can even put it on a tilt mount but I'd call them about the space you have available. The only thing I didn't care for was SMB doesn't use stainless steel hardware...spec that if you want it. There are some pros and cons with SS.

Dave

[sdwindansea]

Thanks Dave. Since we live close to the ocean I'll try to spec stainless steel. I can always change it out myself as well if needed. So, you have the panels with the junction box and not the MC4 connectors? I just want to make sure I order the correct one. I also sent an email to Peter at SMB to confirm that they can supply the mounting hardware and connections.

[daveb]

The way I read that link, yes I think so. It has a 4x5 box mounted to the bottom of the panel. I don't recall if SMB mounted it there or it comes that way. SMB can tell you for sure if you give them a call.