Aduviel,
To answer your question about the PV Charge cable have 2 pairs of the solar connection cables. They are in parallel just like @johnmiller described. I have my solar cable pair connected to the just any pair of 1 red and 1 black of the PV Charge cable to my EP500. I tested them with any combination works fine. As long as 1 red and 1 black. As you know, it is not possible to mal-connect them to 2 red or 2 black on the PV Charge cable. You know what I mean. 
In the meantime, you may want to try again to take your panels outside under direct sun. Then place them at the angle position correspond to where you are located at. I use a free app tool “Optimal Annual Tilt” meter app. It automatic detects your location’s Latitude / Longitude like GPS. It then shows you the solar angle for your panel to be positioned. Next, if you tap the meter display on your phone, then lay the phone on the panels and tilt each panel to fix them at the suggested angle. Check and see any change to the volt and/or watts reading. The app is free with ad, but pretty useful.
Good lucks!
p.s. My phone is an Android phone. I assume the app may have IOS version.