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Forum Index : Solar : Where to get cheap panels.
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renewableMark Guru  Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Ouch, getting spanked by the master. I'll shut up now. (ignore my bad suggestion) Cheers Caveman Mark Off grid eastern Melb |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
I have no Shame, I'll put in a lame idea the more knowledgeable can shoot down :0)... What about tapping into the diodes at the back of the panel and take the power from 2 of them instead of 3? Should give 126W from a 190 panel. Could also run another controller at a lower power from the 3rd leg to get the full value from the panel at workable outputs. |
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Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 1024 |
Years ago we had a small solar panel with a switch on the side, we could have 6v or 12volt output. Had a larger one, took the cover plate off the back and connected another wire to the second or third diode giving a different voltage and still the same amps. Perhaps that will still work with a 190w or 250w panel, voltage might be out of range? I would try it if I had spare panel sitting around. Cheers Aaron Cheers Aaron Off The Grid |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Gee,got me worried now ,after reading the posts. You see,I,be just bought 1500 watts plus the inverter second hand off an installer,who says everything is working , for $370. That’s 8 x 190 watt panels plus a ok inverter. Close to home ,pick up Monday. I,be now got 2500watts of second hand working,I hope, panels all the same size physically plus 2. Sunnyboy inverters.. I used ,top hat, gal steel purlins with insertion rubber insulators between for mounting them . Took 2 of us 2 days easy working to erect on a outside flat pegoda area attached to the house and gets full sunlight early morning to last light . Bruce Bushboy |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
You can check if the panels are current cec approved here here and inverters here Cheers Caveman Mark Off grid eastern Melb |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Thanks Mark , I'm not too worried about regs,(can't understand some of the reasons and why ), but I suppose they gotto tick all the safety boxes . More of a "fiddling around" hobby for me -only two of us here, so the power bill is fairly low,I just use my "hobby" solar for the power and lights in my workshop . One day , I'll get around to having a sparkie connect it all up to the existing grid connected 1 Kw I have officially connected . Bruce Bushboy |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
There were 250W panels advertised on gumtree yesterday, 50 of them for $20 ea. Unfortunately I was away and didn't see the ad till I got home at 2:30 am this morning. I sent the seller a message but predictably got a reply they were all gone. I would have bought the lot at that price. Most likely someone did! They are out there but the demand does seem very high. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Why don't you ring a few local installers and ask them if they have any from pull downs, and leave them your number for any future ones. 50x @$20each??? OR 20x $50 each Cheers Caveman Mark Off grid eastern Melb |
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Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
At that price the seller would have been beating off buyers with a stick. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
50x $20 Picked the wrong time to go away.  Saw the ad and thought I'll take 30 of those. Then I thought about it and thought pigs arse, I'll take the lot or however many I can get. Wishful thinking. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
ouch Cheers Caveman Mark Off grid eastern Melb |
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| fightmaster1165 Newbie  Joined: 14/12/2017 Location: United StatesPosts: 3 |
I'm also looking for second hand solar panels but I am wondering if you can test their efficiency somehow before you buy them? I was reading that efficiency can make a big difference on ROI. (https://greentumble.com/most-efficient-solar-panels-on-the-market/ ) I see you guys don't mention about it. It's not important? I would like to get some monocrystalline panels. |
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oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
When the energy comes for free, efficiency is really only a problem for the real estate you need to use to get the required kw of panels installed. If you use twice as efficient panels ( if they were available) , you can halve the roof space.... but thats the only difference. Your buying panels of so many watts..... not so many square inches. The only thing better efficiency has bought to the table thus far, is more powerful panels in a reasonable and manageable size. The carry on they perform in the press about getting slightly better efficiency each year.... is meaningless unless your a manufacturer, where glass surface area counts towards the cost. If you can squeeze twice the wattage into the same package size, then there is a huge difference to manufacturing.... but the end user will only notice less roof space being used for the same number of kw. ..........oztules Village idiot...or... just another hack out of his depth |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
My test for efficiency is how efficiently can I turn $$$$$$ into watts. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
Exactly the way I calculate it. How quick will I get a return on my investment and be making money from it in saved power charges? The thing I have learned/ come to believe with solar is that trying to gain efficiency is a waste of money. Solar efficiency is pretty much a misnomer. Cost of trackers for instance... better off to buy a couple more panels and have them fixed than try and get more from fewer panels. Less complication and definitely less to go wrong in future. Framing to get the correct angle, Just buy a few more panels that will get you a greater yield without the fuss and complication of tilted racking and put them at your roof angle whatever it is. Micro inverters, same thing, each one costs nearly as much as another panel so put up more panels and you are way better off..... and you won't have to replace the panels when they fail in 5-10 years and so it goes. Can't put all the panels facing north, put them east/ west, calculate the losses and add more panels to compensate and get your desired output. Might cost you $2-300 when dealing in used panels which will be repaid in 6-12 months. That sort of ROI is the efficiency you should look at. Efficiency is only chasing the small fry. Put on another couple of panels into your array and you'll do better over all for usually less cost and effort. A lot of efficiency things only work on sunny days as well. Having more panels on a cloudy day is pretty much unbeatable by any optimization technique. I realise you are asking about the efficiency of the panels specifically but it's a moot point in the same light as what I'm talking about. Buy an extra panel or 2 in whatever you get, don't count them and your 12 panels will be the most efficient 10 panel string you ever heard of! Might cost you $100 for the extra 2x 250W used panels. Alternately, if efficiency is a big concern to you, only option is to buy new panels for $300+? ea where you can choose the exact panel you want. You'll pay a lot for a panel that is the most efficient at 2% more than another but on a 5kw array at the end of the year, the number of cloudy/ sunny days and even smoke from a summer bushfire or how many birds crapped on your array are probably going to be a bigger influence on your total yeild. If buying used, your chances of buying the most efficient panel are pretty much zero but the watts you get for the $$ will be unbeatable in efficiency over any super efficient panel setup. |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Dollar return is irrelevant to me as I am only concerned about off grid. Making lots of watts when the sun is shining is also irrelevant. My focus is getting the most power when the sun is not shining brightly. So for me flat-mounted panels work best in cloudy conditions, keep in mind you can be off by 20 degrees in full sun and still have little effect. For mounting I use 30mm SHS 1.6 gal with upside down T's welded on with predrilled holes and drill holes for holding the panels in the right place. Costs a fraction of the aluminium stuff unless you can get it secondhand. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429 |
Here's some correspondence that I got yesterday from one of my wholesale/retail suppliers regards PV panels here in Europe. There not the best brands but some of the Monos have reasonable costings. Trust this helps. ............................................... We stock a large range of PV products, both on and off grid, at very reasonable prices and are able to offer a next day delivery service to most areas of the UK. I can easily set you up with some logins to our website, where you can access pricing. If this would be of interest? When you are able it would be great to discuss how you are finding the PV market and how much you are doing; what kinds of jobs (domestic, commercial, off-grid etc)? We had some module reductions recently to give you some idea of pricing. From From Panel........... Stock ....... .......£/W ...£ per Panel Trina 265W Silver Poly 540 .... 0.328 ......86.99 Trina 275W Black Mono 160 .... 0.392 107.80 Trina 300W black Mono 309 .... 0.441 132.30 Perlight 260W Silver poly 336......0.318 82.81 Perlight 260W Black Poly 53 ......0.352 91.73 Perlight 250W 54 cell Delta Black206 .... 0.421 105.35 Perlight 300W Black Mono 105 .... 0.431 129.36 Sapphire 270W Silver Poly 773 .... 0.326 88.11 Sapphire 270W Black Poly 280 .... 0.343 92.61 Sapphire 285W Black Mono 1312 .... 0.387 110.33 Q Cells 295W Black mono 284m .... 0.406 119.97 Also, coming in late January 2018 we have some new panels joining our portfolio from Q-Cells. The new Q.PEAK DUO - G5 315W Mono. Featuring the new Q.ANTUM DUO, Split Cell Technology, which enables a particularly high performance on a small surface and with outstanding performance in real conditions. I've attached the datasheet for you. We believe pricing will be 0.45/W, but this may well improve. We will also have in the Q-Cells 285W Poly at around 0.36/W, again the datasheet is attached. Everything is possible, just give me time. 3 HughP's 3.7m Wind T's (14 years). 5kW PV on 3 Trackers, (10 yrs). 21kW PV AC coupled SH GTI's. OzInverter created Grid. 1300ah 48v. |
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| fightmaster1165 Newbie Joined: 14/12/2017 Location: United StatesPosts: 3 |
That's clear enough and it makes total sense. Thanks a lot for taking time to explain it for me. This really made my day. No way I'm going to buy the 'most efficient' panels. I thought efficiency is the most important, since the panels need to collect as much sunlight as possible to produce electricity. But I'm more interested in ROI rather then technical efficiency percentage numbers. |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
Mate, I was the same. You read things and get an idea in your head and until you do the hands on, you can't realise. I bought some panels and had them in the back yard. Managed to angle 10 of them to the " correct" angle with some scaffolding and the others were lying flat on the lawn. Did a lot of learning with things then went to put them on the roof to get them out the way. I had already looked at the PVwatts calculator and saw that the lattitude angle everyone suggests was NOT the ideal, a fair way from it but about 10o less was. I thought I'll have to build a frame as the shed roof is a fair way off. Before I worked out how to do that, I put the panels on the shed roof which is 5 and 13o. I thought how bad is this going to be and went back and crunched the numbers again and saw that over the 4 months of summer like weather, having the panels at these angles instead of the 34 ideal or even 25o I calculated was actually going to give me MORE power. Crunching the numbers through the year, I worked out the total losses and then did some more numbers ( and I was abysmal at maths at school let me tell you!) and figured how much a panel put out and how many I'd need to make up that shortfall. Imagine my surprise ( and laughter) when I worked out that ONE additional 250W panel would give me more power at the shed angle than having them on the frame would at 25o. Ya, put up one more panel flat on the roof or put up 20 on a frame I have to purchase the steel for, weld up, mount to the roof, mount the panels on and hope to heck I didn't underestimate that wind even as I thought I was going overkill and the whole lot don't end up flying through my windows or worse still, the neighbors. I can get a 250W panel here all day for $75, the last lot I bought cost me 40 Ea. I was worried about framing the things on a tilt because we get real bad winds here and having them sticking up would make them like a sail and even if they didn't blow off the roof, they would put a lot of strain on it that may damage the roof structure itself. Having them flat on the roof takes that away as well as the significant work and cost in building let alone buying a frame. The other thing I found was that having the panels facing south instead of north at that shallow angle wasn't the end of the world either. Not ideal BUT there are times I can even see myself they are going to get more sun that the " correct " direction. I looked at putting panels on the west 34o ( co incidentally) pitched house roof where I have an acre of space. Hmm, that seemed poor efficiency. would be a LOT better flatter like the shed roof but that's pretty full now. OK, to get 5kw like yeild, IE, 5KW worth at the right angle at the right direction, how many more panels will that take on the west roof to make up the shortfall? Wow,4 panels, 1 KW extra and I'll be a touch ahead... especially on cloudy days when essentially there is no sun direction. Can't beat cubic ( or square) inches as they say. 20 panels on the west roof would be a doddle. I have space for at least 40 panels before I even have to start turning them to worry about getting them all up. Now lets say I have to pay $200 for those 4 panels. What will they earn/ save me in power? Even facing west on the 34o angle, those panels where I am will net me $329 worth of power in a year. No brainer. Funny thing was, I have only just moved into this place and had a misconception about the north roof which is hard to see being to the side of the block. Got up there, took some measurements and if I can't get 5Kw up there I'll certainly get 4.5! :0) Might put some cheap lower wattage panels on the west side and hook them to the hot water heater through an inverter and a booster if not prime power supply. The internet is full of Bullship basically. I find that in every single interest and reference I have every had and found info on. Most people just repeat what the guy before them did or said who copied the guy before him who copied.... and bugger all people actually question it or look at what applies to them in THEIR situation. Crunch the numbers, run the sums, ask the questions why and think about how something applies to YOU. Ask why you are doing something? Whats the benifit, what problem is it trying to overcome? Do you actually HAVE that problem or does it apply to somone else or is just more over the top theoretical internet paranoid hype because there is a ship ton of it out there believe me. I am/ was into Veg fuels forums. I can tell you about 95% of the preached practices and rules are complete and utter garbage. Same with my trade of Photography. I could not begin to tell you how many things I have not only done but made a very profitable business out of where every single person that replied to my technical questions ( easy over 100 now) told me it was an impossibility. Even after a couple of years of doing it, they accused me then of Lying!  You can learn a LOT from the net but it's really important to believe no one, get your hands dirty, crunch the numbers, write down the results and see what is best for YOU. As I said, solar efficiency is like a lot of other things, a load of BS designed to part you from your money by giving misinformation. While ever you have space for another panel, especially a used one, you are always better off putting up more than spending money trying to get more out of a lesser number of panels. |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
Sometimes you want the highest efficiency- I paid nearly $700 for 500w of panels, but they HAD to be as small as possible and put out as much as possible- simply because I wanted as much charge as I could, yet had to fit on the roofracks... My new place on the other hand will be repurposed ex ongrid panels, as many as possible within reason (but I can be rather unreasonable at times lol) and will be at ground level (40 acres gives you lots of space to play with obviously) so cheaper lower efficiency becomes more important, size much less so I must say, after comparing a dual mttp controller with east/west split, in comparison to a north only one, there is a lot to be said for abandoning the `north, north and only north' approach, the east/wester one is simply miles ahead on total power made over the course of a day, the inverter hits it max several hours before the north one, and stays there long after the north one is dropping in output Yes it has half of its panels not contributing at the beginning and end of each day, but the east for morning/west for arvo panels are still pouring out full power for that array long before/after the north panels are dropping away rapidly And also noticeable is that like flat panels that work well in overcast conditions, the east west split seems to be ahead of the north facer (possibly because they see `horizon to horizon maybe??) they are fairly `flat' about 30deg or so- we had a full day of heavy overcast and showers, it randomly hit 5kw at times during the day from 9 onwards, never once dropped below 1kw from 7.30 to 5.30, well above the north only one I had to admit at first I was dubious that we would get a halfway decent result with 5.5kw spread in an east/west only config (there is basically no north roof, what little there is has solar hws, maybe room for 2 or 3 panels and thats it) but I'll admit I was majorly surprised by the output levels- we are getting pretty much full power at 10 in the morning if not earlier. and getting 2kw out at 7.30 in the morning |
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