Mc4 parallel connectors

[Julian-Indaiatuba]

Hello,
I have Growatt SPF 3500 ES hybrid inverter and now have nine 330W solar panels connected in series as the inverter can handle up to 430 Vcc.
To add more panels I would have to build two arrays of 6 or 7 panels, and connect the two in parallel.
I would really like to know if it’s OK to use good quality 2 to 1 MC4 parallel connector (See picture). That would be so much easier I would imagine.
Thanks in advance for any advice or suggestions.

 

[sunshine_eggo]

Check parallel connector ratings. MC4 are only rated for 30A. If you're under the rated current, should be fine.

 

[Julian-Indaiatuba]

Check parallel connector ratings. MC4 are only rated for 30A. If you're under the rated current, should be fine.

Thank you for your reply.
I will be joining two strings of about 300Vcc and 9.5A each, so I suppose that should be fine.
Should I use a 20A fuse or maybe just a little higher?
Thanks again.

 

[sunshine_eggo]

Thank you for your reply.
I will be joining two strings of about 300Vcc and 9.5A each, so I suppose that should be fine.
Should I use a 20A fuse or maybe just a little higher?
Thanks again.

You technically don't need a fuse with 2P, only 3P and higher. The panels themselves will act as a fuse if there is some sort of catastrophe.

If you want to apply a fuse, the best way would be to put a single MC4 fuse in each series string equal to the max fuse rating listed on the back of the panels.

Without specific guidance, the general ruse is any fuse or breaker should be 1.25X the maximum rated current of the wires/device.

 

[Julian-Indaiatuba]

You technically don't need a fuse with 2P, only 3P and higher. The panels themselves will act as a fuse if there is some sort of catastrophe.

If you want to apply a fuse, the best way would be to put a single MC4 fuse in each series string equal to the max fuse rating listed on the back of the panels.

Without specific guidance, the general ruse is any fuse or breaker should be 1.25X the maximum rated current of the wires/device.

Thank you very much.
I think I won’t be having too many problems connecting those two arrays then. If I use a MC4 fuse in the strings, is that only on the positive wire, or the negative also?

 

[sunshine_eggo]

(+) only.

 

[BradCagle]

I use these https://www.amazon.com/dp/B09R1V4Z78?ref=ppx_yo2ov_dt_b_product_details&th=1

They are beefier than others. One caveat is the male mc4 connectors have an insert that will pull out when you disconnect. I suspect the insert is there to make better contact. Anyway the solution is "just don't disconnect" If you must just be aware you'll need to place the insert back into the male connector.

I replaced all my branch connectors with these because the others I've used would get hot, and disfigure. My strings run real close to 30amp.

 

[Julian-Indaiatuba]

(+) only.

Thanks!

 

[Julian-Indaiatuba]

I use these https://www.amazon.com/dp/B09R1V4Z78?ref=ppx_yo2ov_dt_b_product_details&th=1

They are beefier than others. One caveat is the male mc4 connectors have an insert that will pull out when you disconnect. I suspect the insert is there to make better contact. Anyway the solution is "just don't disconnect" If you must just be aware you'll need to place the insert back into the male connector.

I replaced all my branch connectors with these because the others I've used would get hot, and disfigure. My strings run real close to 30amp.

Thanks for your input and suggestion. I‘ll order some of those.
I don’t think I’ll get much higher than 20amp, so those should be perfect!