Homebrew Solar Panel Updates

[andyman5002]

Title says it all, just wondering how everyones panels made from ebay cells, or any other cells are holding up? How long have they been in service? Whats the output like? Any bust cells? if you could do something different what would it be? Any problems with condensation?

I'm asking because I'd like to know what to expect from my panel when its completed and what I can try to do to make it last longer. I know we can't really expect them to hold up as well as a commercial one but we can hope .

Andy

[Volvo farmer]

I built six panels last winter, 72 Ebay cells ~100W, wired for 12 or 24V. I'm just now getting around to building a rack to hold four of them. I had my cells sealed up between two sheets of tempered glass just like a double pane window. A couple weeks ago, I went to move the panels and I caught an edge of one on the concrete floor, just barely touched it but POP! shattered the whole front pane. Next day I went to move another one and POP again, shattered another front pane.  Still got four of them to put in the frame and I just happen to have two more sheets of glass to replace the busted ones eventually.

I'm on track to have mine installed this fall and I'll post a diary when I get it done.

I'd suggest being careful with tempered glass if you don't have a frame around it. I'm taking old washing machine hoses (I have a lot of free ones) and slitting them lengthwise and putting them around the edges of the glass before I mount them on the rack, I do not want to hear that POP again. Millions of little glass diamonds all over the floor.

 

[andyman5002]

Hi Volvo farmer thanks for the reply. I'm sorry to hear about your breakages, I hope it get fixed soon. Looking forward to seeing some pics of the finished array. Should provide some decent power.

Ive built a wooden frame for mine and will be using tempered glass on the front. I think I will have a problem with warping on mine so I'm going to try and brace it with steel angle some how. Ill be using 36 cells in mine, I'm at the soldering stage at the moment, I did a few last night a broke a cleaned cell not very happy about that. Ive soldered half of the required cells, not sure how these solders are going to hold up over time. Ive been trying to think of a way to mount the cells that will allow for them to be easily removed so they can be changed or re-soldered but it seems too difficult.

I don't like this wax covering scheme that the seller uses. I can see the benefits in delivery but getting it off is a pain. Ive still got about 30 cells to remove wax off.

Andy

[picmacmillan]

hello...i built 7 panels with 28 cells in each...i too have had some damage due to moving them around too much, but i do use them and one panel charges my stereo at my work site, all the rest will be used soon for my off grid home......i like them for the cost, which was about 17.50 canadian per panel..for 46 watts or 64? cant remember....i have had some condensation.. and some burnt marks...damgae also occurs from chunks falling off, but overall, i am happy with them...they were alot of work, and i am kinda not sure if i would do it again..but....for condensation what i did was insert a small q-tip ..the plastic part in the middle has a very tiny air hole, and it releases any moisture so far., and is small enough that no bugs can enter either..,that took care of that little problem....

hope this helps...good luck on your project...pickster

[andyman5002]

Hi picmacmillan, there some nice looking panels there. I would have liked to use glass for my panels but I think I would have struggled even more. I like that there wont be any warping. I agree with you about not wanting to go thought it again. For me cleaning them is definitely the hardest bit so far. It takes forever to clean one cell. Ive not tried putting them in the oven, I just polish them with spirits. I may have to try the q-tip idea if I get condensation.

Thanks Andy

[Volvo farmer]

Back when Pickster and I bought our cells, they were not being shipped in wax. Byron was just wrapping them up real good in bubble wrap. That sounds like a real pain to clean those up, I'm sure glad I didn't have to do it!

[BurksFallsMan]

Picster: Where did you buy the cells ?

Will you be north in the near future ? I will be going soon.

Wilson

[amiklic1]

I was preparing to upload some update and pictures about my panels I am currently building...

We were building the panels like NICE (search the web)project suggests (the same principle as double pane insulated windows). We were using double tempered glass (front and back), alluminium hollow square pipe to hold the "silica" inside, to prevent the condensation, glued with SIKA Tack drive car windows glue, alluminium profile 20x20x2 mm (U-type) to hold that all together.

We sold some panels to the guy that mounted them onto te boat, and after a while he called us to inform us tht the panels are wet inside. We went to see what's happening, and it seems that the SIKA glue (silicon) wasn't thick enough, and that inside pressure "blow" it from between two glasses.

We tried some other things when repairing those panels, and after many trials and errors we can say it's all OK for a long time now.

Now, we use double glass (tempered, 4mm each), 3x3mm rubber glued to the glass with adhesive butyl rubber (both side adhesive, it uses in window making industry) to glue the glasses to the rubber, SIKA Tack drive 8mm deep between the glasses (it gets 11 mm in total inside the glass- 3mm rubber and 8mm SIKA silicone). After we leave it for a dy to stay and dry, we apply ARGON (Ar) gas inside the panel, to ensure no condensation appears. We apply plenty of gas, more than it's inside of the panel (6 l/min applied for two minutes - x2 (two times)). We take two bus bars outside the panel between butyl rubber and 3x3mm rubber, and after we glue it all together, it simply cannot leak.

We teated the panel with the internal pressure for more than 1.5 Atm (Bar) and nothing happens. We test each panel for condensation so that we put it on total sunshine for a hour or so and after that we throw plenty of cold water on the upper glass. After many errors and condensation, it seems everything is OK now.

Here are some pictures of error panels, as well as two ones we finally installed on the boat:

[andyman5002]

Yes it is a pain and I wish they were just sent in plain bubble wrap. This is where most of the breakages have occurred during polishing them. Also when you melt the wax in boiling water and separate them it seems to pull of the front tinned tabbing on some sells which is a pain. Not sure how this affects the cell performance? Does the power just flow down the white lines and out the wire, or does it need to have contact all the way along the wire? I have tried to exclude these cells from my panel so far, but I think I will have to try to repair some because I'm running short of 'good' ones. So far it has been a painstaking process which has not been too fun. The turbine project was much better and I'm looking forward to completing this one and getting it out of the way. I'm sure that I will have many more problems to come.

Andy

[andyman5002]

Hi there amiklic1, looks like you've got it down to a fine art. The argon is a nice touch and is a far superior design to mine. I'm sure with all those precautions taken moisture won't get in. There very professional looking panels, good work. I don't think I will be able to get argon in my panels, I just hope they hold up the way the are. Does anybody know how pyrocasto's panels are holding up? My panels are basically just a copy of his which I thought were quite a good solution using wood. The modular design is great. I saw his panels cracked how did they get on after that?

Andy

[luckeydog]

I bought cells off eBay by the pound about 68 watts of cells

for 25 dollars some were broken when I received them but most were ok.

I used glass out of a screen door. (double pane) and separated the two pieces of glass. laid up the solar cells pretty side down and soldered the cells in series until i reached 17.5 vdc. Then I used large globs of silicone on the back of the cells and laid the other piece of glass back over it.

now at first I did have problems with water condensation I believe from the silicone and moisture in the air. So I drilled two holes in opposite sides of the aluminium frame and silicone small 1/4 inch tubes in them. this has taken care of the moisture problem although I live in a very dry climate. I have seen other people use mineral oil inside there panels. I have not tried this because I just haven't had any other problems with water inside the panel. I have been running the two panels for over two years now and they still work great. 150 watts a little over 75 dollars invested not bad.

I am not saying this is the proper way to do it ... it is just the way I did it.

Luckeydog

[Volvo farmer]

I just looked at cusdn's auction today and he says he will send these in bubble wrap if you ask him to. You'd probably be responsible for breakage though. I think it's important for the ribbon to be connected the entire length of the cell for full output. I had some success tacking it back down with solder on the cells I had with this problem. Don't know if the wax would make it harder to attach or not.

[Volvo farmer]

How do you get the wires outside the panel?

My technique was much the same as yours. I'm pretty sure the glass shop that sealed them up used that adhesive butyl rubber. I never did put mine in a frame because I couldn't scrounge aluminum cheap enough. Nice pictures, looks like you have a good technique there.

[amiklic1]

I am using the interconnection wires to take them outside the panel. The same ones I'm using to interconnect the cells. That way, as those wires are vry thin, and still a good conductors, I can put them betwwen the butyl rubber and 3mm square rubber used as distance between the two glasses. I am using the alluminium profiles because it cost me just 8 US$ total for each panel, and it's better and easier to mount. Also, it' uses as protective frame for the glass. I'll make a schem and upload it, soon, to make it more clear.