On my TT, I have two 128 watt (24 volt) panels (256 watts at 24 volts total), two group 24 batteries, and a 30 amp MPPT controller (room for more panels if needed). On my TC, I only have one 150 watt panel (18 volt), one group 24 battery, and a 15 amp PWM controller.
When you shop for the panels and controller, watch the voltage on the panels. Some put out 24 - 48 volts, and higher. PWM controllers won't take the higher voltage and drop it down to 12 volt. MPPT controllers do.
With MPPT controller, you hook it up to battery bank first. That tells the controller to put out 12 volt power. Then your panels can input up to 48 volts, into the controller.
If you buy 18 (or less) volt panels, you can use a PWM controller.
