Need help with DIY panels, only getting half power

[Guest]

Hi,i am new here.i made diy solar panel 800w and solar cell efficiency is 21.6% and each panel out working volt 11 and 7.5Amp.here temperature is 40C.everyday generating 2.5unit to 3unit.i used 4mm glass and slygard 184 encapulation.max power output half.why i am getting half power.i used mppt 40amp and 24volt system.please help

[jflorey2]

Hi,i am new here.i made diy solar panel 800w and solar cell efficiency is 21.6% and each panel out working volt 11 and 7.5Amp.here temperature is 40C.everyday generating 2.5unit to 3unit.i used 4mm glass and slygard 184 encapulation.max power output half.why i am getting half power.i used mppt 40amp and 24volt system.please help

Is your voltage or current lower than expected?

As a test, take an unencapsulated cell (hopefully you have one or two left) and use that as a reference. Compare your panel to that (multiply voltage by N cells of course) by measuring Isc and Voc. Then do the same behind a sheet of glass in case the glass is unexpectedly filtering part of the spectrum. Make sure the temperatures are similar when you compare the two.

[J.P.M.]

Could you describe the method you used to calculate the 21.6 % efficiency ?

[SunEagle]

Could you describe the method you used to calculate the 21.6 % efficiency ?

That is probably what the seller of those cells told him.

[littleharbor]

Without linking the listing from eBay here's the title, Most listings of these sunpower cells listed boast this efficiency.

10 Pcs 3.34W C60 DIY Kit Flexible Solar Cell Sunpower Maxeon 21.8 High Efficiency.

Cell efficiency and finished panel efficiency are two completely different things.

[Mike90250]

Is your glass Low Iron glass, or simply stuff from the hardware store ? Low Iron glass is more transparent to the light than regular glass

[titosairbagsvc]

Need help, i have 9 panels Mono 300w Open-circuitVoltage(Voc) 40.10v and Short-circuitCurrent(Isc) 10.23A, and want to add a Poly panels of 315W Open-circuitVoltage(Voc) 46.2 and Short-circuitCurrent(Isc) 9.01A.

Can i use theme together in serial connection??, pls need som help, thanks a lot

[Guest]

I used low iron glass here is link https://www.environdec.com/Detail/?Epd=11718

[Guest]

As I told here I have 800w solar panels and each solar panel voc 13v and 7.5 Amp in 40 to 50 degeree Celsius and 30 degrees Celsius at each solar panel give 8.34Amp.

[Guest]

Total voc is low 88volt.it should be 104 but showing 88volt and then I connect mppt then volt showing 69volt and 6Amp.

[Mike90250]

As you have discovered, there is the possibility of so many failure points in DIY panels, all I can say is that I hope you have not invested much money in them
Most cells sold as surplus, are production line rejects, and are not prime cells
Soldering properly and cleaning residue is difficult
Sealing the panels to prevent moisture degradation is impossible without a vacuum heat sealer system
Any of these faults, along with wiring mistakes, leads to trouble.

Trouble shooting starts with testing each panel by itself, under load.

[bcroe]

I found it extremely difficult to get 6 inch square (4W) cells working without any fatal cracks
developing. The only success I had at all was with 3 X 6 (2W) cells. Encapsulated, but a
test point was put at the end of every column to help tracking down faulty cells (which I then
shorted out to salvage the rest). Bruce Roe

[Guest]

I used NSP 6inch high efficiency 21.6% made in taiwan solar cell.I invested 2100$ for 800w solar system(off grid).only slygard for 700$ and 500$ for solar cell5.37w(160pcs) low iron glass 200$.I used 15SQ045 bypass diode.each solar panel have 20pcs solar cell and two bypass diode installed.Should i install ideal diode for block reverse current/volt?

[Guest]

in short i am getting loss in Amp.here is solar cell detail:-Max. Power:5.37W,Material:Monocrystalline,Open-circuit Voltage :0.699V,Filling Factor(FF):83.59%,Open-circuit Current:9.908A,Conversion Efficiency:21.6%,Working Voltage:0.597V,Working Current:9.456A.

[jflorey2]

. . 500$ for solar cell5.37w(160pcs) . . .

So you spent $500 for 860 watts of solar cells. If you are just doing this for fun, great - but you should probably be aware that you can solar for cheaper than that in finished panels. Prices in the US were 55 cents a watt before the tariffs, now they are up at about 70 cents a watt.