Response from FR Customer Service

Yes, the two small cables at battery are the solar connections.  Meter is always a good idea. +1 to OG regarding fuse addition.

Of course you can. You can install ceiling fans in your own house too, but you have to ignore the instructions in the box which say to have a licensed professional do it. FR is just protecting itself from incurring legal liability by someone “misunderstanding” their instructions.

Several others have noted that there are two wires leading in and out of that area, one end of each going to the roof for solar input and the other ends going to the battery area for the solar charge controller output. If you think you might have that situation then you can confirm it without cutting the wires by connecting the wires to each other at the battery end (not to the battery) and then going on the roof with an ohmmeter and checking continuity there between the two wires. If you have continuity then disconnect the wires at the battery and confirm that the two wires on the roof now show open circuit. Then you can cut the wires and install your controller in the space provided and the solar module on the roof.

Do please also install an appropriately sized fuse at the battery positive terminal as part of the install, otherwise if you get a short between the battery and the controller you can start a fire. You don’t need a fuse between The solar module and the controller, it won’t do anything anyway.