A solar system set up for your RV is simple once you understand how it all works.
It starts with the solar panel taking energy from the sun and converting it to electrical power you can use. They typically operate around 17 volts and are rated in watts for how much power in amps they can supply to charge your batteries. They operate around that 17 volt mark so they can handle the peaks and ebbs of the sun at high noon or lower light and still be able to pass along the 15 or so volts your batteries need to be charged with.
The solar panel must pass through a charge controller. This is the brains of the operation. They control the voltage and prevent damage to your batteries. They come in all kinds of prices and qualities. The more they cost, the better job they do.
The batteries connect directly to the charge controller. The charge controller then knows when to let the energy through to charge the batteries and when not to once the batteries are charged. The better charge controllers let you set the voltages for your exact brand and type of batteries.
The Inverter then takes the energy the batteries have been charged with by the solar panel, and invert it up to 110 volts you need to run your appliances.
So the solar panel feeds the energy to the charge controller that regulates the charging to the batteries for the incoming flow, then the Inverter flows that energy back out "the other side" of the batteries for you to use your appliances.
In the picture below the light bulb is being fed directly from the solar panel through the controller. This port is for very light loads such as 12 volt lights. It is usually called a Load port. It will usually cut off the 12 volt light bulb before it drains down your batteries too far. It is rarely used but is there if it is needed. It will not handle bigger loads like a coffee maker, or any 110 volt appliance, those must go through the Inverter.
We are always available to explain the pro's and con's of which components are best suited for your use.