Have purchased seven 485 watt solar panels for the roof of my trailer.
What I can say first is you are making the classic newbie mistake of buying stuff first before understanding what you need. A 7 in most combinations is NOT a good choice because its a prime number only divisable by itself. What that means in the real-world is that you can only have a combination of 7 panels in series or 7 panels in parallel to make a functioning system.
Follow the advice that BM and SSE are giving you and come up with a plan first before buying anything else. Make an itemized list of what you want to power. Keep in mind that anything that either heats or cools typically draws far more power than electronic items like a TV, or DVD player.
The first thing to understand is the basic electrical mantra,
in series Volts add while Amps stay the same. In parallel Amps add, while Volts stay the same. That idea guides all the math you will need to do.
As BM asks, first determine the specs of your panels. That means tell us the Vmp, Voc, Imp, Isc. Do you understand what those terms mean yet? Start there. Get those numbers, and get back to us.
Make the itemized list of what you need to power. Get those numbers and get back to us.
Recommendations can be made AFTER you provide us with the required information. These people here are willing to help you, but as indicated, you have to be willing to contribute some of the effort yourself.
