In part one of this series, I stated that we are designing a basic 12V solar charge system costing $3500-5000. You can build a larger or smaller system, this just gives us a starting point so I can restrict my discussion to components that fit this system.
So, how many solar panels can I add to my solar charge system if I have a 40 amp charge controller. Forty amps is 480 watts for a 12 volt system. However, you do not want to exceed the capacity of the charge controller, when the sun is high in the sky with clear blue skies, your panels will frequently exceed their rated capacity. So, let's leave a 10% margin of error (480 watts - 10% = 432 watts). Therefore, we can safely add 432 watts of solar panels to our system.
Solar panels are cheaper per watt the larger the panel you purchase. Typically, one 200 watt panel will be cheaper than two 100 watt panels. You will also save on mounting hardware, wires, and such by purchasing higher capacity panels. Panels also come in various sizes and it is important to match the panel size to your available space. This image shows the various components of my solar charge system (except batteries and solar panels); it is important to place the charge controller in an area that will get some circulation, charge controllers have cooling fins and need air circulation.
I will cover solar panels in Part 7 of this series. For my system, I choose four 100 watt panels because this fit the space I had available for my unit and this did not exceed the capacity of my charge controller. At a future date, I will install a second charge controller and four additional 100 watt panels.
There are many choices for charge controllers and books, these are the ones I have purchased and had good luck using. I wish you all well.