Trying to Decide Panels and Controller

[shucksan]

Hi,
I have a small trailer and it comes with 200w solar panel on the roof. It is possible to add a second 200w and maybe a 3rd 200w panel.
My dilemma is if I add a 3rd 200w panel. If I add a second panel then they can go in parallel and the 10awg wiring can support that but if I add a 3rd then the current will likely exceed the wiring.
If they go in series then the shadow tolerance will go down. 2 in parallel and one series or 2 series and one parallel will kill the output when combined.
It is like, there is no good way to do this.
It seems either all series or rewire the cable going from the roof are the only options or only put up 2x200w.
Is there a right way to do this that I'm not aware of?
Thanks for any input.

 

[HRTKD]

My approach on shading is that if one rooftop panel is shaded, they're all probably shaded. Consequently, I wire panels in series. This applies to those panels that are in the same plane. I have four panels mounted on the rear of my RV. Two on each side. They're tilted at about 10°, so they're not in the same plane and I wired them 2s2p.

Three panels is an odd number so it makes for a difficult wiring configuration. Wire in series (3s) and see how it goes. If that doesn't work then then change to 2s and use a second charge controller for the third panel.

 

[WorldwideDave]

5 panels, 7 panels, 11 panels, 13 panels, 17 panels, 19 panels, 23 panels, 27 panels also difficult to figure out. Separate arrays and MPPTs is my approach. I have 30 panels total now but not all match anymore. Adding smaller rv panels does not make sense when house / commercial panels cost same and are more watts.

 

[HRTKD]

Adding smaller rv panels does not make sense when house / commercial panels cost same and are more watts.

This is true. On a small RV it may be difficult to fit residential size panels. Bang for the buck, residential is the way to go.