# Reject solar panels for \$0.58 per Watt

Solar Expert Posts: 462 ✭✭
Hey guys, check out what I found. What appears to be 6x6 cell polysilicon 54 cell frameless, junctionbox-less panels selling for \$0.58/W rated 150W. They are supposed to be rated 215W based on cell type and cell count. But since they are rated 150W, they most likely have internal cell shorts or dead cells. They are 1.443 meters square, then efficiency is 150W/1443W = 10.4%. At 215W they would be 14.9% efficient. The cells appear to be wired in series for 27 Vmp but the center taps are a little of a mystery. I think they are there for bypass diodes, but how would they be wired? What do you guys think? Are they worth 37 mile trip to go see them myself? I am looking for something real cheap like this to cover 350 sq. ft. of roof space. I have been looking around for cheap solar cells in \$0.4 - 0.6 /W range to make experimental hybrid solar thermal / PV collectors, obviously for off-grid non inspected setup.

• Solar Expert Posts: 741 ✭✭
Re: Reject solar panels for \$0.58 per Watt

Without frames there is a good chance the glass could get cracked. The glass has good impact strength on the face. But just a tiny/light nick on the side and the glass in going to break.
• Solar Expert Posts: 462 ✭✭
Re: Reject solar panels for \$0.58 per Watt

After doing some more calculations, this panel appears to be not 150W but more like 92W. On the site it says Voc = 16.2 and Isc = 7.5A. I assume they actually measured these, since open circuit voltage and short circuit current are easy to measure using the multimeter. The values they give for Vmp and Imp equal 150W. That totally disagrees with their Voc and Isc values, because Vmp = Voc * 0.802 and Imp = Isc * 0.94, so Vmp will always be less than Voc, same with Imp. I suspect they just passed on what the manufacturer told them for Vmp and Imp but actually measured Voc and Isc, since measuring maximum power point value would involve hooking up MPPT controller, battery, waiting for 1000W/m2 sun and keeping the panel at 25 deg. celsius. Therefor, Pmpp = (Voc * 0.802) * (Isc * 0.94) = 91.6W. That increases the price to \$0.95 per Watt, and lowers efficiency to just 6.3%.

If you are wondering where I got these Vmp and Imp formulas, I calculated them from Evergreen PV panel datasheet. I assumed Vmp : Voc ratio is similar between polysilicon panels of different manufacturers.
• Solar Expert Posts: 462 ✭✭
Re: Reject solar panels for \$0.58 per Watt

On other hand, their short circuit value may be measured at partial insolation. Eh, the only way to know for sure is to go buy one and compare side by side with known good panel. Or wait untill they do proper side by side comparison.
• Solar Expert Posts: 481 ✭✭✭
Re: Reject solar panels for \$0.58 per Watt

How would you mount these frameless panels to your roof?

I would be extremely suspect of mounting any "reject" panels on my roof. Sounds like a fire waiting to happen.
• Registered Users Posts: 4
Re: Reject solar panels for \$0.58 per Watt

they look like the ones that brightwatts makes and my boss said they were selling framless 200 w panels for \$.60 a watt he was just there yesterday
Off grid.
Temporary system while i build house
8.5 kw pv, 70kwh's tesla model S batteries, 4548 xantrex
2 60A xw cc 1 80A outback cc. 25kw diesel gen
Looking at skybox for 20kw ac 18.5kw dc pv when done

Re: Reject solar panels for \$0.58 per Watt

Laminates are not hard to work with many huge installations use laminates only without frames. They use rubber gasketed clips.

One guy glued four blocks of hard plastic to the back of the laminates and then attached the blocks to his mounting frame. There are other ways to mount laminates, its not that hard but you need to do it right.

Moving the modules around just requires you to be more careful like all sheets of glass, it is tempered safety glass the same as used on all modules.

As for fire you should never (this should be pointed out to everyone), use them on anything but an offgrid appliacation thats 12,24 or 48 volts. Never use them on a grid connect system.

It was di9ffuclt for us to measure all two containers we got. We did out best. For anyone who feels we took advantage of them we will gladly make good on it.

These modules should not be labeled as defective, they are simply unfinished as they were left over after the ends of a model run, have only minute tiny tny mostly invisable blemishhes if any at all. To me they all look perfect. There might be an exception but we will give you your money back if you are not totally satisfied.

John
Owner of Sun Electronics, Int., Inc.

As for the people who like the price of these perfect looking crystalline laminates and who purchased them and are happy customers we wish you would tell more people.

The thing that amazes me about these modules is that they qualify for the 30% Fed. investment credit/rebate. Yes hard to believe and it is a rebate still available till the end of the year. So you could say they arfe only .40 a watt.

At .50/watt these laminates are cost effective against the utiltiy in most places
• Solar Expert Posts: 462 ✭✭
Re: Reject solar panels for \$0.58 per Watt

Hello John. Many of these laminates you have posted on your site do not have pictures. Also price is listed at \$0.97 per watt and not \$0.50. Are you testing them yourself or you go by what the factory says? It would be great to see side by side comparison with a brand name UL rated module. Or test them using the light table. It could be easily built with an array of 50W MR16 reflector Halogen lightbulbs.
Sunelec wrote: »
...These modules should not be labeled as defective, they are simply unfinished as they were left over after the ends of a model run, have only minute tiny tny mostly invisable blemishhes if any at all.

Well, they do seem defective based on the electrical specifications you provide on your site. As I pointed out in my first post of this thread, these modules should be rated 215 Watts based on cell type and count. Nowadays, 6x6 inch cells supposed to perform at 4 Watts a piece. 150W / 54 cells = 2.78 W/cell average. That is poor performance that suggests some kind of defect or measurement error.
• Solar Expert Posts: 313 ✭✭
Re: Reject solar panels for \$0.58 per Watt

Hey,

I bought some of those panels recently but with frames. I have recently installed on on a fishing boat and the owner could not be happier and the panel works. So maybe in a years time I may have some more data on how it stand up against some rigourous testing on the high seas since the fishing season start next month. I have done some research and have found that most those panels and laminates are actually astropower panels. I have unearthed some old pictures and spec sheets from early 2000 and they are identical in nearly every respect. I have done my own testing at noon for open circuit it they match those of the respective astropower panels. BTW astropower was bought over by GE so some of those GE panels on sale are the same Astropower panels sold under a new brand. Either way I was happy to get those panels at those great prices and my clients are happy for the good price I can offer them so they feel safer on the high seas. My only problem is that I can't get more of them at the prices I bought them for a few weeks ago. Thanks John.

Cheers...
Damani
• Solar Expert Posts: 462 ✭✭
Re: Reject solar panels for \$0.58 per Watt

OK, that's good. Did you happen to measure power output? How's that inverter effciency test going?
• Solar Expert Posts: 755 ✭✭
Re: Reject solar panels for \$0.58 per Watt

looks like sunelec has more of these panels at 0.78/watt.
it would be pretty easy to make aluminum frames for them. also pretty easy to buy the junction boxes off ebay. @ \$18.50 each plus \$14 for the aluminum frame that bumps up the price/watt to \$0.93.

but from what I've read an off grid system is pretty expensive due to batteries so the savings you have on getting non UL panels is eaten up by having to buy batteries.

there are of course drive drive applications like irrigation, pumping water, etc.
• Solar Expert Posts: 755 ✭✭
Re: Reject solar panels for \$0.58 per Watt

There is a \$180 crating fee for these frameless panels and the price went up to \$.88/watt, so final price is more like \$1.06 per watt by the time you add junction box, etc.,

not that amazing considering labor involved.
• Solar Expert Posts: 755 ✭✭
Re: Reject solar panels for \$0.58 per Watt

looks like they sold out in about a week. I bet most of the people buying them dont' realize how much work it will be to fix these reject panels.
• Solar Expert Posts: 755 ✭✭
Re: Reject solar panels for \$0.58 per Watt

Looks like they have some more reject panels in stock at 75 cents a watt, and 10 panel minimum order.

However they are handyman specials, looks like you need to be good at ripping off a bus bar and resoldering it and making sure you use the right encapsulant so it doesn't corrode over 25 years.

Anyone every repair a panel like this? how hard was it and more importantly how do you encapsulate the wiring to prevent the environment from destroying it?

"The laminates are great, brand new, the laminates are made by one of the top 5 Mfr.s in the world. They ripped off the frames and J-boxes so no one could buy them, ha, ha. You can cut out the bus bars (we have a movie somewhere showing you how) solder extensions , slip those thruough the clamps in the J-Box (you can get ours or buy your own) and Silicone it down, clip off the excess tabbing and snap the clamps tight and your done. I would cover the connections with silicone as well when your done. Any other repairs are fairly simple if needed but 99.9% need nothing more done."
• Registered Users Posts: 1
I buy rejected and B grade solar and window tinted film for export. Please let me if you have any information.