RV solar systems

Brooks

What is the minimum size cc do I need to get to handle 400 watts of solar panels??

Estragon

It depends on system voltage, and to some extent the location, panel specs, and controller. 

For 12v in very general case, you could use 400w x 75% for warm panels ÷12v = 25a.  A more conservative approach would be 400w STC output ÷11v deep cycled charging plus a bit of room for temp derating = 40a controller.

Jeremy

To determine the inverter size we must find the peak load or maximum wattage of your home. If 400 watts, the inverter size is 400 watts. 

mike95490

Jeremy said:

To determine the inverter size we must find the peak load or maximum wattage of your home. If 400 watts, the inverter size is 400 watts. 

If you want your inverter to last more than a couple months running at 100% capacity, you size it so sustained loads are only 75% of max. and it's surge capacity is larger than any appliances with motor start up surge (fridge, well pump, HVAC blower)

Estragon

I think the question was controller output capacity, not inverter.

fratermus

Estragon said:

For 12v in very general case, you could use 400w x 75% for warm panels ÷12v = 25a. 

Should we specify that this case leverages MPPT's ability to clamp power if we do get more than expected in some conditions? I'd hate to see someone toast their PWM controller

Estragon

Yes.  As mentioned, the number is a very general case.  OP hasn't even said what bank voltage is, let alone controller, panel specs, etc.