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Forum Index : Solar : Repairing PV solar panels
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SparWeb Senior Member  Joined: 17/04/2008 Location: CanadaPosts: 196 |
Hi, Inspired to add a comment by this post from Bruce. I recently tried repairing a few defective PV panels. They were going to be scrapped but the glass was perfect. A friend of mine, who found them, figured the diodes inside would be at fault, and he proved his point to me by repairing one. Then I took a turn, replaced the diodes in another (finding a bad cell connection tab in the box too). We got a bunch of "bad" panels back to working 100%, all for the cost of a few little schottkey diodes. If you're interested in reading more, I wrote it up in detail here. Steven T. Fahey |
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| Boppa Guru  Joined: 08/11/2016 Location: AustraliaPosts: 814 |
I have found that the diodes are often the cause of otherwise visually 'perfect' panels not working and are, as you found, easily replaced... For cheaper panels that have 'plastic' front panels, (usually epoxy poured over the cells) I used to find that heating/cooling contraction seems to 'pull' the soldered strips off the cells- this can also usually be fixed by carefully heating the epoxy with a heat gun and (very carefully lol) cutting it apart and lifting the epoxy off the connection- usually retinning the cell with silver solder works and allows the resoldering of the connection strip, then reseal with 24hr epoxy (not the 5 minute stuff- it goes ff in the sun very quickly) I have several garden lights etc at various places I have done this to and they continue to work well (ETA Well done to those on that web page, shows how easy it can be) One thing I have found is that 'potted' electronics can often be easily 'dug out' the silicon rubbery ones with a sharp modelling knife/scalpel, the hard shiny epoxy stuff degrades with heat, and can be softened with a heat gun and cut with a sharp knife, I actually have an old $20 iron I bought years ago that I use (on plastics only) to 'dig' into the epoxy and scrape it away with a small screwdriver etc... One thing to note is any time heat and plastics/epoxies are mixed, it's best to do it outside, and probably a good idea to use a respirator as well... |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
I have a couple of shattered panels I coated with clear lacquer over the glass. I use them for battery charging and Maintenance with a couple of cheap fleabay controllers. Had them going 19 months now and they are still working fine. Power output is slightly down which I take is from all the cracking and crazing of the glass. I note the comment at the end of your write up sparweb about donating panels to schools and 3rd world countries. Here recycling panels, as in tearing them apart, is a hot topic. We have laws that are primarily designed to keep the solar industry profitable that that seem to change every 6 months and make perfectly good working panels illegal to remove and replace even if they were only removed to do work on your roof. Same with inverters, If one fails you can't put a newer one on, it has to be the SAME one as what came off. As such tens of thousands of perfectly good panels are completely wasted every year. It's all done in the name of " safety" of course which is a load of BS. If they are safe enough to remain on peoples roofs they are safe enough to re use. I have come across a couple of guys buying used panels and filling containers with them and shipping them off to the middle east. One guy I came across had been going round picking them up with a large trailer but was making enough out of them to have bought a 2 ton truck. Reckoned he was doing very well out of it. We are all supposed to be so environmentally aware these days and conserve resources, energy and minimise emissions but we have idiotic rules like this that purposefully set out to waste things well short of their design lives all in the name as profit. Completely typical of the hypocrisy here. I spoke to the local scrappy couple of days ago. He reckons he gets panels in on occasion. He's going to ring me when he does as I have offered him a better deal that what he can make out of them but still cheap as chips to me. I'll upgrade the used panels I have if better ones come along and the lower wattage ones I'm going to use as the roof for a new shed I'm planning. Might Only hook the panels up in winter when I need more power but either way, will still be cheaper for me than conventional roofing materials and the structure of the roof itself is virtually unchanged. I'll just seal them together with silicon and all should be fine. It it doesn't work for some reason, not the end of the world to replace them with tin. I'll bet plenty of places in the 3rd world would be very happy to have a roof made of panels or even just A panel to give them power for there meagre electrical needs. They would probably cry if they knew we were throwing away perfectly good working ones and wonder what the hell we are thinking. I wonder that myself a lot too! |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
Thats crazy....  The offgridders and 'grey nomads' (retirees in what would be called RVs in the states) love the widespread availability of second hand panels here- ebay, gumtree, even here at the shed you can see some incredibly cheap secondhandies for sale Shed thread 190w or thereabouts panels for $20..., I regularly see 240-270w ones for $40-$70 ETA, it is common practice to swap panels on a string out as a new panel will often be different in its outputs to older ones (not really required imho), but I haven't heard of any 'regs' requiring like for like replacement on inverters etc, which state is that?, it's definitely not the case in Qld |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
This morning I have lined up 5Kw of 250W panels for $500. They are Trina's and I know they have has some issues so I'll be looking them over carfully. I know they had water ingress problems and I'm wondering if there is a way to test them? Maybe check the resistance from the leads back to the frame? not sure, see if I can find anything online or if there is indeed a way to test them. I'm amazed at how many people have stupid ideas about what old panels are worth. the money asked by some is laughable. I have had people tell me all about how they paid thousands years ago as if the things are still worth that. forget the age, forget they are probably sub 200W panels and forget the price has fallen to a fraction of wht they were, it's like they want to be compensated for the money they spend and have have got a return on, probably with .60C fit they got for years when the things now don't owe them a penny. There is one guy on Dumbtree atm that wants $2200 for a 4.5KW system and is coming back with insulting replies to offers of what the things are actually worth. Not hard to pick up a new 6.6 System here in Syd installed for $4K. May not be the best but at least if nothing else you can get manufacturers warranty on the panels and inverter which is a lot more than you can get with used and they will be legal to hook up to the grid. The ignorance and greed of some not to mention the belligerent attitudes never ceases to amaze me. This tool will probably have the things advertised for 6 Months before he finaly wakes up that his price is stupid and then will sell in the end for less than the offers he's knocked back. Done that before. Made an offer and got rejected then month or 3 later made a lower off they have accepted. Makes me laugh every time. With the panels I'm Hopefully getting, can never rely on private sellers on these sites) I'll replace some of the lower wattage panels I have in the better areas of my roof space. Really wondering if I should get 10Kw worth? If they look as good as they are made out I might do that. |
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| SparWeb Senior Member Joined: 17/04/2008 Location: CanadaPosts: 196 |
Davo, Boppa, Thanks for the extra ideas! This lucky friend of mine seems be getting lots of panels this way. Maybe it's less of a problem here in Canada, or maybe we just aren't as clever as you Aussies! I am still getting a grip on how big a problem this might be, here. I'm going to give a try at examining the guts of an Enphase inverter next. I'm worried that it may be potted through and through. Have to get it open to be sure. Steven T. Fahey |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
Looks like the seller is going to come through. Ordered 21 panels to replace one I broke for another set a while back. Have been using 2x 175's in parallel in it's place to replace it which has been working well but having 20 panels instead of 21 will be a lot neater layout wise. Mrs is funny. I messaged her at work and said can you grab $600 cash while you are at lunch for me please. She comes back " WTF you want $600 for? " I said "I found some solar panels I want to upgrade the ones I have already with" She says " Ok, that's fine then, I'll bring it home tonight, Is that enough?" She knows we save so much with my solar mucking around she doesn't care what it costs because she knows we get it all back and so much more. Have to pick up a roll of cable as well next week. I was playing with another broken panel today I got an idea for. I ordered one of those Voltage converters from fleabay and hooked it to the panel and an LED down light. Worked great. Even late this afternoon with the panel totally in shade and standing against the shed upright facing to opposite direction to the setting sun, it still lit the LED. Was a bit dim but I turned the converter down in the daylight as the led seemed too bright. Might test the voltage the transformer runs the light at and then set the converter the same. I'll have to look up whether the converter I got is buck and boost or just buck. If it's not B&B I'll get one that is and hook the light(s) to that and put them strategicly around the shed where it's dark and I have trouble seeing in cupboards etc. I still have room on the roof for about 3 panels so should run a couple of 12W leds till quite late in the afternoon especially if they are facing the sky. |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1123 |
Great idea, I have a 175w 18vmp panel on the roof, all it does is power a few (8) of those 10w cobb led modules inside the garage via several current limiting buck regulators. The garage only has a single window that gets the sun late afternoon, so is very gloomy, now its lit up like day soon as the sun is up. Cheers Mike |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1577 |
Do you have any links to the Lights and the controllers you bought Mike? there are hundreds of them on fleabay, it would be nice to know what the " Proven" ones are. I ended up getting 6 KW of the panels and an extra to replace one I broke. They look real good. I went over them all carefully and the guy selling them Checked them all as well and Meggered them so can't do more than that. When I arrived a guy was there with a Hire ute loading up 60 panels. I asked what he was going to do with them and shrugged and said I don't know. I said you bought 60 solar panels, hired a ute to get them and you don't know what you are going to do with them??? He said I am going to send them to Africa and he was trying to fill a container with them and was complaining about the cost to send them there. I was thinking I bet you will make a fortune from them though! He was giving the guy selling them a hard time and being a pain in the Butt so I didn't bother telling him where I knew there were thousands of the things interstate. Now the work starts. Figuring out which ones I'll replace and where the best place is to put these is and then taking the old ones off and putting the new ones up. |
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