Noob question about series versus parallel.

[attomica]

Hello All,
I'm doing a 6' x 10' cargo trailer conversion. I would like to connect my four 100w Renogy solar panels in parallel to my Renogy Rover 40-amp MPPT charge controller inside the trailer. My understanding is that configuration will allow the panels to operate independently so if one malfunctions the others will operate as usual. Can I just run the wires of each panel to a 4-to-1 MC4 branch connector to give me one negative wire and one positive wire to go through the trailer roof to the Rover MPPT? It's a small trailer so any wire runs won't be that long, maybe 10' max. I bought the Renogy components as a kit with cables and everything, but it looks like this kit was designed to connect in series because there is just one set of cables besides those coming from the panels. I saw on another webite that a parallel set-up would need something called a combiner box and I've not heard of that.

I'd be grateful for some guidance.

 

[NVS]

It better if you can connect your panels in series so voltage is added but current stays the same. This allows you to use smaller wire size and saves money.

 

[rmaddy]

I wouldn't worry about a panel malfunctioning. Shading is much more of a possible issue to deal with. It depends what else you will have on the roof. If there is nothing else on the roof that might shade part of one or two panels at a time then putting all 4 panels in series would be better. Or put them in 2S2P (put 2 in series, 2 more in series, then connect those two pairs in parallel with a pair of Y connectors). Just make sure the SCC can handle the voltage of the panels. Post the specs if you are not sure.

If you do have lots of potential shading issues then putting all 4 in parallel can work. You need to fuse each of the 4 panels. Use can use inline fuses along with the 4-1 connector. Just make sure the 4-1 connector is rated for the combine amperage of the 4 panels in parallel. If not, you may need a combiner box to handle the higher amperage.

Either of the above setups will only need one pair of wires through the roof to the SCC inside the trailer.

 

[attomica]

Thanks for your replies. They're quite helpful.