Series or Parallel for my RV?

[joeright]

I'm new to solar and electrical installations.
I'm planning out a solar system for my camping trailer. I'm leaning toward 3 Renogy 175w panels on my roof.


I was thinking connecting the panels in parallel because that seems to be better under shading conditions. Then I calculated how many amps would be going through the wires & found that mc4 connectors (even make your own) are usually 30amp max and mc4 crimp tools for larger guage wire really aren't available.

The panels on my RV would ALL have scattered / full shading most of the time where I camp. Would that be the equivalent of a "no shade but cloudy day" where series works better anyway as far as having enough voltage from the panels? I also live in New Jersey where it's cloudy most of the time. I'll have a 12volt 200-300ah lithium battery.
I will have an mppt controller.

I'm looking for advice on the best set up for my situation. Thanks.

 

[time2roll]

Shade is bad either way. At this level either way is about the same. Series makes the wiring a bit easier. There are bypass diodes to allow sunny panels to push power through the shaded panels with some power loss. Eventually you may seek out the sunnier sites at the campground. Biggest issue with series is to not exceed the controller max voltage. Best to stay 10% 15% below the max to allow for cold conditions. The listed panels would be at 69 volts.

For parallel, a combiner box can be used to transition to larger #8 or #6 wire down to the controller. Or run each panel separately to the controller.

My three 225w panels are in series. Shade definitely reduces power and still with minimal conservation I have never run low.

 

[mikefitz]

The most yield from 3 panels in shaded conditions would be to use 3 MPPT controllers, one for each panel. A Victron 75/15 is not too expensive ( around $65 each) that compares well with a single controller , Victron 100/50 at $185.

 

[joeright]

Thanks for the input. I hadn't considered using multiple controllers. I'm not sure where I'm going to fit a single one yet, though. I have a Casita trailer. I love it but there's really no spare space. I only do things "by the book" especially electrically for safety. In this case that means good airflow & clearance per manufacturer specs. So it will have to be in the living space somewhere, preferably close to the battery.