Panels are now running - Pictures Posted

[RCpilot]

I quit building panels for a few weeks to mount up the two I had finished. A friend gave me an old Channel Master satellite mount and I readily took him up on it. A few trips to a salvage yard got me the unistrut, wire, and pole to mount it on. Owner of the yard is a friend. The two panels are in series outputting 39.5 volts to a BZ MPPT 500 charge controller charging a 12v 1500 AH forklift battery. I really need those other panels, these two are just tickling the battery. The mount is setup for 8 panels total . Ever since I mounted them, it has been cloudy, rainy ever since with a couple of days where I could at least get some readings. Even on the sort of sunny days it was very humid with the sky looking more white than blue. I was getting almost 8 amps into the battery out of the two panels. I am hoping for near 10 on a really good day as each panel puts out 5 amps. 80' of wire across the yard #8 fine stranded. The next two panels will also be added in series. RedRock's tracker is running the actuator and works perfectly. On the cloudy days the panels just go to the middle position and pretty much just sit there bumping back and forth. Right now it's running from a battery sitting on the ground and isn't finished yet wires are just hanging. But, It works!. Two limit switches had to be added to the mount as the actuator has a rotating style switch in it. More to come including around winter a Hugh Piggot 10' windmill.

[AbyssUnderground]

They look very smart and very neat, well done! 8A would be a dream for me. I only get 1.5A and thats on a very good day. Time to move the angle of my panels I think. They've been at the current angle all summer so time to tilt them to an autumn/winter angle.

Here are the images RCPilot said were posted:

[TomW]

Abyss,RCpilot;

Not sure who's panels are in those photos but I have a question.

I always wonder when folks mount these aluminum frame panels to steel do you worry about corrosion from dissimilar metals?

I was paranoid so Mine use stainless nuts and bolts with a stainless nut as a spacer so the 2 metals never touch. With nearly a $1500 investment I felt a few more bucks for stainless hardware was justified.

Not sure if that was overkill or not or if it even matters.

Cheers.

TomW

[rossw]

At the risk of being dumb.... doesn't that double the "dissimilar material junctions"?

• Steel to Stainless
  
• Stainless to Aluminium
  
  

In order to ensure no such points exist, would decent nylon bolts do? I don't think they lasted very well out in the weather though.

Then there's the whole issue of local code "requiring panels be grounded" - so I suppose you have to introduce some sort of acceptable bonding to them anyway.

Don't know if yours are the same as mine, Tom, but all my panel frames are anodised which makes them largely inert. I've seen no sign of corrosion, but then I mounted the panels to aluminium frames and mounted the frames to the steelwork.....

R.

[Volvo farmer]

Tom,

Those panels do look awfully nice to be homebrewed don't they? I do see a little gap in the aluminum at the corners, which I've never seen on a commercial panel, so maybe it's true? I'd certainly like to hear more about the construction technique of these panels, because they do look awfully nice.

I also used stainless hardware, but no spacer nut. My steel was painted, my aluminum was anodized. I considered corrosion a non-issue. Worst case scenario, the aluminum rots in ten years and you move the whole thing down 3", re-drill holes and prevent metal to metal contact in the future.

Stainless is neat because it looks as good ten years down the road as the day you installed it. I just took the lug nuts off the old '79 F150 to replace a flat tire and I wouldn't have minded a bit if the engineers at Ford had decided to make those parts out of stainless :-)

[RCpilot]

I hand made them including tabbing and soldering all the cells.

[RCpilot]

I like it when I do work good enough to fool people. Guys, It's true, I built those panels from Ebay 6" PowerMax Siemens solar cells Rated at 6amps and .55 volts per cell. I bought in bundles of 50. I bought enough cells to build 4 panels including breaking several as I learn to solder them. In another diary entry I explained my build procedure. I will recap. the fronts are 1/8 tempered regular window glass from a local glass company here in town that I had made to my size. The extruded aluminum frame around them is actually used for windows. The cells are silicone glued to the glass by small dabs on the tabbing between the cells. The glass has a 1/2 X 1/16 aluminum frame around the perimeter to space the aluminum back of the panel away from the cells as not to break them. The perimeter frame is silicone glued to the glass to seal it. Then between each cell is a small 1/2" square (you can see them in the picture of the panel) of the same aluminum to space the back so that each cell has the back supported away from it. This ensures that the back won't ever touch the cells. The back is .040" aluminum panel that is powder coated on one side and as you can see the green in one picture, is anodizing. Then, I silicone glued fiberglass window screen to the back panel to insulate the back from the backs of the cells just in case the back for whatever reason might touch the backs of the cells. Then the glass was laid face down, cells face down and the back silicone glued to the perimeter frame sealing it perfectly. The only hole in the entire assembly is where the large tabbing exits the back of the panel to the junction box and another tiny drilled hole at the opposite end of the panel. THEN, I connected a can of freon to the tiny hole and displaced all the air out of the panel with freon gas, finally sealing both holes with silicone. No moisture problems hopefully. I have posted more pictures of the various components including a side shot of the extruded anodized aluminum window frame that goes around the panel. In the same picture I am holding the rubber gasket that captures the assembly and supports it in the aluminum frame very securely. My panel design is loosely based from two books I bought "How to build a Solar Panel" by Phillip Hurley and "Laymen's Guide to Solar Cell assembly" Using those books I came up with my own method of panel construction. The displacement of air was my own Idea. Look at the pictures I have posted in "My Pictures" to see my various components of construction. I plan for these panels to last a long time and took extra steps to insure that they will. I have a total of $280 in each 100 watt panel.

Kelly

[RCpilot]

I renamed my files a while ago and killed the ones that AbysUnderground had posted above. I just now figured out how to include my pictures in a posting.

Kelly

[Chagrin]

The fact that a current-carrying path exists is what's important. The number of metal junctions is not really relevant. In this case, when the entire set of metals is covered in water, the lowest in the series (the aluminum) will oxidize first.

Basically, if you have a loop from metal1 to metal2 to an electrolyte (water) back to metal1, you've got a galvanic circuit. It really is, in all respects, a battery.

[Nando]

RCpilot:

I congratulate you for such GOOD AND CLASSIC well done job.

Indeed, learning to do it, prior tackling the job, insures to One self to have a good well done job.

spending some few extra dollars to lean the proper steps and procedures do give us the chance to do a much better job.

I have always suggested :

First :READ the instructions,

Second: Read the instructions;

Third: practice before tackling the job.

Nando

[DamonHD]

Yes, indeed.

In software terms: "practice before tackling the job" is "make a prototype that you must be entirely prepared to throw away" (given that you now understand the job a lot better).  If you can salvage any more than the experience gained, it's a bonus!  As a sometime CTO I agree with this wholeheartedly...

Rgds

Damon

[RCpilot]

Everyone, thanks for the great comments! I used to be a toolmaker and I guess it's in my blood to do precise work. Ever since I put the panels outside in the Tracker I have had nothing but rain and partly cloudy days and can't get a good reading on their output but I have seen around 8 amps for them once or twice. I am hoping for 5 amps per panel. They are wired in series going to a BZ MPPT 500 charge control. Unfortunately I am trying to charge a 1500 AH battery and really need my other two panels built and even more after that. The mount is setup to hold 8 panels total but cash flow will limit how fast I can fill it up with homemade panels. Today it's outside to try to wrap up the tracker setup as It's just rigged right now and needs the wiring cleaned up and the battery mounted in a box or something to protect it. I have enough small solar cells to build a small 10-15 watt panel to charge the tracker battery but there just isn't enough hours in a day to get it all done. If there is anyone interested in building panels I am willing to share the techniques used to solder the cells, etc. I broke several in the learning curve and think I am pretty good at it now and have a good procedure worked out. The construction of the panels are in a previous diary entry.


Kelly