What if a cell breaks?

[pyrocasto]

Sorry for another thread.(also did this once but it didnt come up).

Lets say, your panel gets hit by a rock or bullet, or anything. How do you remove and replace that one or two cells you have broken. The way most people do the soldering it makes it near impossable to do(I think). Right now I am soldering extra ribbon on the back the be fed through the back of the "cell rest plate" to be soldered back there. That way it will be easy to replace one or two if they break. You would just desolder them from the back plate. Please though if anyone has a better way of doing it let me know, because I spend extra money and twice as much time doing it this way.

All help will be greatly appreciated,

Chris Casto

[iFred]

VERY INTERESTING!!!! I gotta think for a bit on that one.. Very neat idea...

[tecker]

  How do you plan to keep the plywood from warping . This is the only reason the glass is used . The expansion and contraction is the reason metal is a problem. This looks like a well conceived back plate Electrically it's very flexible. Post your results .

Roof material get's very hot so It may well last  . You might use polyurethane thinned to absorb deeply into the wood.

 

[pyrocasto]

The plywood shouldnt warp since it will be on the inside, sealed away from elements. Now the big plywood panel to carry it should warp either because of the good sealant. If it does get some warp, I'll just screw a couple square bars on the bottom, if it comes to that.

So I guess for everyone here if your cell breaks your kinda in trouble? Would like to know if I should order another 1000' of ribbon/tabbing or not.

[nothing to lose]

I'm not building cells yet, but got a question on this for ya.

 If I see that correctly, are you soldering a strip all the way across the back of the cells AND running the back of the plywood also? If the cells are wired end to end how about 2 small holes at each joint, one for each cell and solder them there. Sort of stitching them in. Each only needs enough tail to loop over the hole to the next tail, the plywood doesn't need any on the back side for anything and any holding strength is just right at the holes anyway.

Doesn't sound right the way I typed it, I know what I mean, hope you do too. Anyway seems like it would use about half as much ribon if it works that way.

Also not sure how your laying out the holes, maybe one of my tricks will help you on that. When I needed alot of holes exactly spaced in several sheets of wood, like building shelving, I first cut the panels to the size I want them. Then cut a sheet of Peg Board to the same size. Clamp every thing together with peg board on top, count the holes and drill!!

 Every sheet comes out exactly the same without having to measure each one and worry about any errors. Saves time not having to measure anything or just a top sheet. And of course the biggest time saving is drilling 1 hole and getting 4 sheets done, cuts the time to far less than 1/4 of doing each seperatly.

I do that alot when building stuff like 1' deep X 6'wide X 8' tall cases/shelves to store DVD's 8tracks, VHS, Cassettes, etc.. Every thing is a different size so I drill all the up rights for ajustable shelfs. Drill, count 3, drill, count 3

 Most the times I don't care if the holes go to the outside of the unit, if I do care on one I just drill the two end sides seperatly using a little electrical tape on the bit as a stop guide for the depth. Still use the same pegboard piece as a guide though and all the holes come out correct.

I pretty much do the same thing for measuring cuts and other stuff too. Clamp everything together find the center hole and use a pencil to fill them in. Take off the pegboard and connect the dots, normally a pefect straight line better than measuring and using a square etc.. Provided of course you can cut that thick, or do each seperatly and they all still come out the same.

[Aelric]

BTW I think this is an awesome idea.  Modular construction is always a good thing.  with construction like that its easier to wire, rewire, and troubleshoot you're panel.  Just a lil question.  If you have the solar cells setup with a ribbon would it be possible to simply run this to a copper bus bar?  You could attach it with nuts and bolts, amke it even easier to swap out.  That way if you ever had any problems you could simply swap it out, no desoldering at all.

[pyrocasto]

Yes I put a pice of ribbon down the back of each cell to reach the back of the plywood, but it only sticks out maybe 3/4". The long piece you see are the exccess ribbon that already came on the front of the cell, which sticks out 3". I thought about the two holes, but decided that it wasnt needed with the sticky tape. I think this saved a little time in drilling(not much).

Basically, I drew some lines to make rectangles of where I wanted each hole. Then I drew the lines where the wires ran. Like you said I clamped all 3 together and drilled where the wire line(red) met the outside of the cell line(blue). The drawing took about 5 min, so not bad at all.

As for shelves, I kinda cheat. My business is a cabinet company so we have the machine to drill a 2' line or so of holes, for the pegs to go in for adjustable cabinets. Each time I press the trigger I have another 2' of holes spaced 1" apart. It makes that process too easy.

[nothing to lose]

Ok, in the pic I thought it was all the wires you had added, didn't know they were already on the cells.

Be nice to have a drill press like that if I did that kinda work alot. I don't build alot, mostly just my own, so I learn or figure out my own short cuts like the peg board trick. I use that one for lots of things.

If I can get the blades cheap enough I plan to build my own 3 (or more) blade table saw. I need at least a 6" deep cut though. I get slabs from a mill now for fire wood and most are 44" long. 16" is about perfect and over 30" is to big. Sliding a row of slabs into a set of baldes and getting 3 peices at once would work nicely like drilling 2 feet of holes

 I am thinking of using chainsaw bars and chain instead of blades for this, then deepth is not a problem and probably cheaper too.

 Not that I am to lazy to cut it manually with a chainsaw, but I have to unload the truck anyway, might as well be cutting it at the same time then just have to move the pieces where I want them.