Diode?

[sundug]

A friend works for a solar company, they are tossing a bunch of panels, he says they only need a diode. This is getting beyond me, so I was wondering if someone with more knowledge on the subject will advise. Thanks, Doug

---------- Forwarded message ----------. The panels- file:///home/chronos/u-83d974fbc2dab1682c54aab50cec65cc4d043e5e/Downloads/Hanwha_Q_CELLS_Data_sheet_QPLUS_L-G4.2_330-340_2017-07_Rev04_NA+(1)%20(1).pdf

The J box part number is >>
GF20X
http://www.renhesolar.com/products1-tid-20.html

The part number for the original diode in the J box >>
ZJRH HDD624
PST4020

I have found this diode do you think it will work?
https://www.mouser.com/Semiconductors/Discrete-Semiconductors/Diodes-Rectifiers/Diodes-General-Purpose-Power-Switching/_/N-ax1mp?P=1z0w9wk&Ns=Peak+Reverse+Voltage%7c0


I don't understand why panels need electronics between them and the inverter.
Do you have a suggestion or part number on what type of diode/MOSFET I should use or perhaps a few criteria to look for?

Thank you for your help in the matter.Thanks, Doug

[jflorey2]

A friend works for a solar company, they are tossing a bunch of panels, he says they only need a diode. This is getting beyond me, so I was wondering if someone with more knowledge on the subject will advise.

Some notes -

The diodes are bypass diodes that carry current around shaded or damaged areas of a panel. They do NOT carry load current unless there is a fault.

The diode you list doesn't look like a real part number. In general you need a ~50V diode that can handle the Isc current. Shottkys usually work.

I don't understand why panels need electronics between them and the inverter.

They don't. They do not carry any current when the panels are working normally.

This means you don't need the diodes unless you see shade. (However they are very good to have just in case.)

If they are offering them for free, then pick them up and try some Shottky diodes,. STPS30M60ST might work.

[PNPmacnab]

My hats off to cheap bypass diodes. I was recently hit by lightning and it shorted out a bunch of diodes. Haven't done any quantifiable testing on the panels, but they appear to be OK. Actually, I would choose a 30V diode if available cheap because the forward voltage increases over 30V and keeps getting higher as rated voltage increases. Free is free. Just rip them out if not being used in strings. I didn't find any deal on the flat pack with screw mounting on ebay, but they have a lot of barrel types cheap 15SQ045 which could be a pain to mount. My panels had SR2045. I consider low voltage a form of protection.