Thanks for your reply. I already have two 20w panels. And seeing as in winter months we don't get much sunshine and the nights are longer it means the led lights will run for longer. So by having 2 panels I assumed it would be a safer option. And having the panels wired to a charge controller will at least deal with any excess power. Will this be ok?
I haven't bought the cable to go from the panels to the charge controller yet. But as the two panels are next to each other I want to join the two panels together (black to black and red to red) using a weatherproof junction box and then take a single pair of black and red cable to the charge controller. Question is, Do I need to put some sort of signal diode at the end of each panel before it gets combined with the other panel to prevent each panel from sending current back to the other panel?
I will try and find a link to this info and post if still interested.
When combining multiple solar panels (depending on voltage required) you will run them in parallel. The way you described.
You will be smart to add diodes at each panel. When panels start to go bad or even output differs percentage wize the lower ouput/bad panel will actually start to draw power from the other panels. Then they tent to damage those good panels and even burn up catch fire.
Buy a good set of crimping solar connectors so you don't have to put in box. They sell Y connectors for splitting/combining.
For every four panels go up a gauge. If the panels have 18 AWG go to 16 AWG. DC current travels on the outside surface of conductors/strands of wire. So larger gauge more strands = more surface for current to flow easier.
Do NOT use solid core wire. Aka house wire. It is good for AC current because AC current travels through the center. Bad for DC.