So that's what I'm doing. I have 3x6" cells, and each panel consists of 40 cells. The panels are made out of ply wood with 3/4" batten board around the edge. The whole thing is coated in white UV stain to protect from the rain and sun. The plexiglass covers the whole thing. I will coat the whole perimeter with silicone as well. I am connecting 2 panels in series to provide 40 volts. I'm using a powerjack 1200 grid-tie inverter. Does anyone know if I need blocking diodes when using a grid tie inverter?
Typically, with just a single series PV string and a GTI you do not need a Blocking Diode. Google: Blocking Diode, PV Panels, GTI, etc. There are conditions where you do need a Blocking Diode or even several By-Pass Diodes. What kind of Plexiglass are you using? How long do you expect the Plexiglass to survive under the daily heating and cooling cycle? What kind of Silcone are you using? Most tubes of silicone found at Lowe's and Home Depot should not touch electronic components (ie PV Cells, Wires). If you live where the humidty is constantly low then your panels may last for a few years.
I would imagine they should last several years. The panels shouldn't get too hot. The while coating should repel sunlight but not interfere with the solar cells. The silicone I used does not touch any electrical component of the solar cells themselves.
Trapped Moisture is the #1 enemy of DIY Solar Panels. Your dark blue cells will get very warm in the sun and then at night the mosture will condense on the inside of the Plexiglas front panel. Is it your plan to make your panels "air tight" with the moisture trapped inside?
I have vent holes drilled in the bottom edge. The panels will be on my roof, and the vent holes as I said are going to be on the bottom so rain and running water wont go in but it should help.
I noticed that the Solar Cells are recessed down within the Frame. Will the shadow from the frame cause a significant decrease in the output when the sun is at an angle in the morning & evening? Also, that center post, will it cast a shadow on any cells and reduce the output?
I'm sure there will be a slight decrease in efficiency. The center post needs to be there for snow load until I brush them off in the winter. About the possible moisture issue...thinking of some kind of vent holes at the top area as well. Perhaps I will drill a couple holes on the sides, at an upward angle.
Condensation issues with DIY PV Panels ... Sealed PV Panel ... http://www.youtube.com/watch?v=KIijgvubcXY PV Panel with a vent hole ... http://www.youtube.com/watch?v=-uQjm5L9-Tw There is no follow-up as to whether the condensation permanently disappears over time as stated in a comment (or not).
I didn't look at the one without venting because I am venting mine. I would bet he doesn't have adequate venting. I believe you really need venting holes on the top of the solar panels, the end that is higher up on the roof. I guess time will tell on mine.
It is hard to balance "adequate venting" (to let the moisture escape) while still preventing: rain, bugs, mold and mildew from getting in. Have you considered the need to coat or seal all of the uninsulated wiring and soldered tabs to prevent corrosion and/or electrolysis ? Assembling a DIY Solar Panel is the easy part. Keeping it working for more than a year is the difficult part.
Update; So its been nearly a week, I have 4 total panels up. The first 2 panels went up about a week ago while the last 2 went up about 4 days ago or so. We've had heavy rain followed by periods of sun. The moisture hasn't seemed to been an issue. The first 2 panels have had slight moisture build up that went away rather quick. I put more venting holes in the 2nd pair and they don't seem to get any moisture buildup at all. I went and drilled more holes in the first 2 panels, and it appears to be working fine. The holes and drilled in a manner to keep rain out. The holes are cover with screen, so bees/insects/etc should stay out. Functionality seems good so far, they are producing usuable juice till sunset. Pictures are on the way.
you'll notice that one of the panels are incomplete. I ran out of cells, but wanted to get the 4 panels up there and see how they lasted for a month, get the bugs worked out, handle the moisture issue before I spent more money.
The first one is Watt hour charge, and the second one is Power out. This is two years of data, I have three years of data on my other machine. The low dip was when I had all the batteries and controllers in the unheated garage. That was in Jan.2013. I have the forklift batteries and controlers in the basement this year, feb 2014. The Kyocera 135GX panels I have were worth trying to make those homemade panels that use the seconds and turds of the assembly of panels. I also hear those cheaply priced China panels are putting out there true worth. My Free advice is buy the good stuff the first time.
