Solarworld 245 mono need replacements

suntrail · September 2019

Anyone out here have 5 solarworld 245 monos for sale or knows where to get them?
seem to be hard to find.

mvas · September 2019

Discontinued ...

Contact Solar World, ask if any distributor still has old stock

Horsefly · September 2019

Canadian Solar CS6P-250 are close enough on Vmpp and Impp that you could use as a direct replacement, assuming you can find them any easier than Solarworld panels. I though Solarworld went out of business, which would mean you'll need to look at compatible panels.

BB. · September 2019

This has been a problem with solar panels for a long time... The large format panels are available for 1-2 years, then go out of production to be replaced by something bigger/cheaper/better...

Many times, you are left to try and find a panel that will match Vmp (if in parallel) or Imp (if series connected) within 5-10% match (close enough). And if you find an old stock panel, the price is ~2-4x the cost of any current production panel and hardly worth buying.

-Bill

littleharbor2 · September 2019

Craigslist can be a good source for older, out of production panels.

mvas · September 2019

Horsefly said:

Canadian Solar CS6P-250 are close enough on Vmpp and Impp that you could use as a direct replacement, assuming you can find them any easier than Solarworld panels. I though Solarworld went out of business, which would mean you'll need to look at compatible panels.

I think Solar World, the German based parent company, is still open.
Was it "Solar World Americas", their subsidiary, that went bankrupt and was bought by SunPower ?

billybob9 · September 2019

Littleharbor is right about Craigslist, being the best source for used panel. I've been looking for a Canadian Solar CS6P-250 but would need to drive up to LA to get it. To get that exact Vmpp now you might have to do the math and see that 250+250=500. Also 100x5=500. So that would mean, take out two 250W panels and replace them with 5five 100W panels. Not too pretty but 100W panels will always be made by somebody. OK, before somebody comes to beat me up and say "you now have a 300W and a 200W" I'll just say Yeah, this was just a way of thinking outside the box that might need to be used to get around the ever changing BS .

Horsefly · September 2019

billybob9 said:

Littleharbor is right about Craigslist, being the best source for used panel. I've been looking for a Canadian Solar CS6P-250 but would need to drive up to LA to get it. To get that exact Vmpp now you might have to do the math and see that 250+250=500. Also 100x5=500. So that would mean, take out two 250W panels and replace them with 5five 100W panels. Not too pretty but 100W panels will always be made by somebody. OK, before somebody comes to beat me up and say "you now have a 300W and a 200W" I'll just say Yeah, this was just a way of thinking outside the box that might need to be used to get around the ever changing BS .

Just to be clear: As Bill pointed out above, it isn't the watts you need to pay attention to when mixing different panels. Rather it is the voltage and or current. If you are putting to different kinds of panels in parallel, the Vmpp of the two panels needs to be pretty close. If you are putting them in series, it is the Impp that needs to be close.

littleharbor2 · September 2019

Horsefly said:

billybob9 said:

Littleharbor is right about Craigslist, being the best source for used panel. I've been looking for a Canadian Solar CS6P-250 but would need to drive up to LA to get it. To get that exact Vmpp now you might have to do the math and see that 250+250=500. Also 100x5=500. So that would mean, take out two 250W panels and replace them with 5five 100W panels. Not too pretty but 100W panels will always be made by somebody. OK, before somebody comes to beat me up and say "you now have a 300W and a 200W" I'll just say Yeah, this was just a way of thinking outside the box that might need to be used to get around the ever changing BS .

Just to be clear: As Bill pointed out above, it isn't the watts you need to pay attention to when mixing different panels. Rather it is the voltage and or current. If you are putting to different kinds of panels in parallel, the Vmpp of the two panels needs to be pretty close. If you are putting them in series, it is the Impp that needs to be close.

Aesthetically speaking, after you get the Vmp and Imp covered You have size and color to deal with. Most 60 cell panels are within a half inch or so in size. Black frame or clear anodized. black or white back sheet. and, if visible you might want to match the mono or poly cells.

billybob9 · September 2019

Thanks Horsefly, After reading your post I realized that it might be possible to calibrate the Voltage on a panel by just blocking a single cell. When I was testing my "How low can you go" I saw the results of partial blocking of a cell and how it effected the voltage drop. So putting a Happy Face 1 inch sticker in the middle of a cell on a 300W panel might make it a 250W panel. If this works in the long run " Problem Solved ".

BB. · September 2019

NO! Do not block a cell to adjust the panel voltage or current.

It might take out 30 series connected cells and take 15 volts of MPPT Vmp output voltage.

And or it could cause parts of the panel to overheat or a cell to fail.

Solar cells (diodes), the dark (normal panel polarities) go high resistance.

The blocking of current flow is not good.

Bill

billybob9 · September 2019

Thanks Bill.
All the more reason to test this out to see if all of the above is true. This is why I said long run as this would be something that would take time. I don't think Diodes would be effected as they only direct the current flow ( one way ) but maybe. In audio amplifiers, Diodes are the week link.

mike95490 · September 2019

billybob9 said:

Thanks Bill.
All the more reason to test this out to see if all of the above is true. This is why I said long run as this would be something that would take time. I don't think Diodes would be effected as they only direct the current flow ( one way ) but maybe. In audio amplifiers, Diodes are the week link.

No need to test, after a couple weeks, the blocked cell may start to char, and cook the wires on it. You won't see a failure in 30 minutes, maybe 30 days, or 5 months. One day, something will get hot enough, for long enough and it frys.

But it's your panel, have fun.

billybob9 · September 2019

Thanks Mike

I was thinking that a panel that had partial shading of some kind ( tree/pole or what ever ) would be a common occurrence. If these people reported charring or damage to that particular cell in numbers I would be 100% convinced. On a panel Photons are converted to electron. If they are blocked from doing this why would there be heat ? I realize that one blocked cell will effect the whole array ( I've seen it ) but what would cause heat, it's just less voltage. The only way I see this happening to some extent is if the current (like in a big water pipe) is stopped from flowing inside, pressure will build up in all the area before the restriction. Not just at the point of restriction. If this is true then calibration could work for a small amount. The difference of 300W to 250W is only 50W which could be absorbed by all panels before the restriction.

BB. · September 2019

Yes, panels are supposed to survive blocked/shaded cells... There are bypass diodes in most/all modern solar panels as the cells generally have a maximum reverse current withstand of ~12 volts. So, there are bypass diodes every ~24 cells (maximum).

The other issue seems to be that the bypass diodes are not the most rugged of devices on the panels. Diodes have between ~0.5 and 1.0 volts of forward voltage drop (depending on type of diode and actual current flow/temperature/etc.). 8 amps * 1 volt drop = 8 Watts of heating in the bypass diode. Solar panels are constructed of glass and plastic just do not have much heat sinking capabilities--And bypass diodes seem to have a short(er) life in shaded applications (probably because of self heating/thermal cycling).

If/when a bypass diode fails open, then the shaded cell will see more than 12 volts (it could see 300+ volts in a GT Solar array) and the shaded cells will cook/fail as 8 amps is sent through a cell at reverse voltage (8 amps * 12-300+ volts = lots of watts of heating and destruction of the diode junction)).

Would your panel fail right away, probably not. But because of the diode operational functions... You cannot "adjust" Vmp by 0.5 volts at a time via cell shading. A single shaded cell will cause current to flow through the bypass diode for that string...

-Bill

mike95490 · September 2019

A tree or cable shadow, moves during the day, it does not stay in one spot for days on end

Solarworld 245 mono need replacements

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