Adding 6 x 100 watt Renogy panels - which config: 3 serial x 2 parallel OR 2 serial x 3 parallel?

[GetOut]

Hi all,

I am adding 6 x 100 watt Renogy panels - which config: 3 serial x 2 parallel OR 2 serial x 3 parallel?

I was thinking the 3s x 2p would be better due to the higher voltage. I'm using 10 gauge wire with about a 20ft run, so it might not matter. The downside I could think of might be increased degradation due if some shading happens with more serial...but wasn't sure how much of an impact that would be.

Figured I'd ask the experts!

Thanks for your help!!

 

[Ampster]

Higher voltage is always better as long as on the coldest day the maximum voltage does not exceed the maximum voltage of your inverter or charge controller. Voltage is a hard limit. Have you priced two 300 Watt panels in comparison or is space a limitation?

 

[Q-Dog]

What charge controller? It matters.

Another consideration ... With 3 parallel strings of solar panels you need fuses on each string. With 2 strings you do not need fuses.

 

[justinm001]

What charge controller? It matters.

Another consideration ... With 3 parallel strings of solar panels you need fuses on each string. With 2 strings you do not need fuses.

Why do you need fuses for 3 strings but not 2? Even if they were 6 strings they can be combined easily and all under 30a

 

[Q-Dog]

Why do you need fuses for 3 strings but not 2? Even if they were 6 strings they can be combined easily and all under 30a

if one string develops a short the panel wiring can handle the current of one other string going through the short but it can't handle the current of 2 (or more) other strings through the short.

 

[justinm001]

if one string develops a short the panel wiring can handle the current of one other string going through the short but it can't handle the current of 2 (or more) other strings through the short.

its 14gauge wire and has 15 amp series rating with each panel 5amps so can handle 3 strings. Glad you told me this as I was running 3s5p of these panels and assumed it was 10gauge so could combine 6 strings without issue... guess not.

 

[GetOut]

I’ve got a Victron 100/50 for the charge controller.

I have the panels, so I was using what I had. Is there any benefit of fewer bigger panels?

 

[justinm001]

I'd go 2s3p if you're 12v. That'll put you at 15a 40v or so. Best for shading and such.

Bigger panels are lighter and more watts per square foot, but this is just because brackets between the panels

 

[Ampster]

I have the panels, so I was using what I had. Is there any benefit of fewer bigger panels?

Less racking, less connections with bigger panels. More work getting the bigger panels on the roof.