Parallel panels before serializing panels

Can you parallel panels before you serialize them without any issues? For example you have 5 panels in parallel on a 10awg cable at 85.6 Voc / 32.15 ISC and another 5 panels in parallel on a 10awg cable at 85.6 Voc / 32.15 ISC. Can you hook both 10 awg cables together to get one 10awg cable with 171.2 Voc / 32.15 ISC without any issues?

If everything is fine, how does shade work for that setup? lets say one panel gets shaded, does it output 8 panels worth of power?

RJW said:

Can you parallel panels before you serialize them without any issues? For example you have 5 panels in parallel on a 10awg cable at 85.6 Voc / 32.15 ISC and another 5 panels in parallel on a 10awg cable at 85.6 Voc / 32.15 ISC. Can you hook both 10 awg cables together to get one 10awg cable with 171.2 Voc / 32.15 ISC without any issues?

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The 32.15 ISC is the issue.

MC4 connectors are only rated for 30A.

10awg may only be rated for 30A. Additionally, wiring must be chosen to meet 1.25X Isc value.

RJW said:

If everything is fine, how does shade work for that setup? lets say one panel gets shaded, does it output 8 panels worth of power?

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Shade sucks. If you're trying to mitigate shade, you only move to panel configuration shenanigans AFTER you've exhausted every means of eliminating shade.

The proposed configuration may perform a little better than a traditional 2S5P, but you'd probably be hard pressed to measure a notable difference.

sunshine_eggo said:

The 32.15 ISC is the issue.

MC4 connectors are only rated for 30A.

10awg may only be rated for 30A. Additionally, wiring must be chosen to meet 1.25X Isc value.




Shade sucks. If you're trying to mitigate shade, you only move to panel configuration shenanigans AFTER you've exhausted every means of eliminating shade.

The proposed configuration may perform a little better than a traditional 2S5P, but you'd probably be hard pressed to measure a notable difference.

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Thanks for the guidance. I'm about to upgrade from high ISC, low VOC all in one boxes to high VOC low ISC all in one boxes and add a few more panels. The upgrade is not having to deal with growatt boxes failing on me and their customer service ignoring me when I ask for returns. EG4 boxes seem to have better customer service.

In my existing system, the 32.15 ISC hasn't been an issue for me so far. I'm currently using M4 at the solar panels to Y branch connectors rated for 50amps. I also have in line breakers between the M4 and Y branch connectors so I'm guessing the M4 connectors never get amps going backwards at more than 30 amps.

I figure when my new all in one boxes arrive, instead of rewiring everything, I can take the lazy man's approach and just serialize all my 1S5P panels into 2S5P panels by combining half my wires with the other half in serial. I figured if anyone did it and got some stuff happen to them that in theory should never happen, they would be warning people in the forums.

I guess in theory, I'll be losing some power through the longer cables but rewiring everything on the roof is a pretty big hassle.

Just to clarify
That would be 5p2s , not 2s5p.

timselectric said:

Just to clarify
That would be 5p2s , not 2s5p.

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Yep you are correct. My terminology is pretty bad

RJW said:

Yep you are correct. My terminology is pretty bad

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It's a lot to learn.
You'll get there.

I wouldn't do it. The current going into serial set #2 is the full current from serial set #1. The current will be divided between the panels in set #2. At first look, that should be ok, as the panels are all equally sharing the current. But, if any panel has an issue, say a bypass diode kicks in because of shading, then the resistance of that panel changes, and may take more or less of the current of the set. That may overload the panel (or the other panels). A panel designed to carry 10 amps (Isc) may have problems at 20 amps.

This is why OCP is required.
10 locations, in a 5p2s configuration.
5 locations, in a 2s5p configuration.