Renogy 550W Panel system.

[AmpD]

Next question. If I parallel 2 panels I get 28.01 lsc. The MC4 is rated at 30A. This doesn't include temperature corrections.

If I put all the panels individually into a 4 string combiner box will this put them in a parallel output without using branch connectors or will the resulting output be as if they were in series?

So basically I'm asking will a combiner box with 4 panels each plugged in as their own separate string gives me:

199.8 voc at 14.05 lsc

or

49.95 voc at 56.2 lsc

or

Something else?

I saw a thread on it when searching for the answer but the end of it got muddled up so I want to make sure I understood correctly. It multiplies the amps in the combiner box when you run the strings in correct?

If I did understand correctly then if I for example put 2 strings of 2 panels in series then it would look like:

99.9voc 14.05 lsc. for each string going into the box from the PV. Then 99.9 voc and 28.1 lsc coming from the combiner box to the controller.

 

[MisterSandals]

If I put all the panels individually into a 4 string combiner box will this put them in a parallel output without using branch connectors or will the resulting output be as if they were in series?

The whole point of combiner boxes is combining strings in parallel.

49.95 voc at 56.2 lsc

This is 4P from combining 4 in parallel. I think i'd look at 2S2P to keep the amps more reasonable, unless you had shading issues on all 4 panels.

99.9voc 14.05 lsc. for each string going into the box from the PV. Then 99.9 voc and 28.1 lsc coming from the combiner box to the controller.

Yes

 

[AmpD]

Again my thanks Mr. Sandals. As a beginner that was a confusing part of the system. I saw videos explaining the electrical path thru the box and components but not how the amps and volts are translated from input to output at the box. I suspected this was the unicorn I needed to get the 2s2p action going on. I really appreciate your confirmation.

 

[MisterSandals]

I suspected this was the unicorn I needed to get the 2s2p action going on.

To get the 2S part, take 2 panels, connect the (+) of 1 panel to the (-) of the other. That is a 2S string.
Do this with your 2 other panels. That is also 2S (2 in series).
Next you need to connect these strings in parallel.
The easiest is with a simple pair of MC4 Y connectors:

https://www.amazon.com/BougeRV-Connectors-Branch-Parallel-Adapter/dp/B0753X68PS/

This connects each of your 2S strings' (+) together and the (-) together, in parallel for 2P.
Your panels are now 2S2P.

You don't really "need" a combiner box for 28A. The fuses and breakers are nice, especially as a cutoff switch. You will want something as a cutoff switch for convenience.

Good luck!

 

[AmpD]

You don't really "need" a combiner box for 28A. The fuses and breakers are nice, especially as a cutoff switch. You will want something as a cutoff switch for convenience.

Good luck!

Thanks for clarifying that. I was worried about being so close to the wire's amp rating. Breakers and fuses will also be nice to have in place. I was under the impression that some kind of cutoff between panels and controller was a necessity. The maximum series fuse rating is 25A so I thought I would definitely need fuses in place as well.

 

[MisterSandals]

I was worried about being so close to the wire's amp rating.

If its made to handle 30A on a worst case scenario (Isc current backfeed), then it should readily handle the Imp. You can check for warmth in the Y connectors when its working to get an idea if they are stressed.

I was under the impression that some kind of cutoff between panels and controller was a necessity.

It kind of is a necessity while you are messing with your array or SCC. If your array is handy enough to throw a blanket over it, that works too. Working at night works too but most issues with solar happen while the sun is up...