Not sure how big the system is.
I like something like this for small systems...
As shown,
The PV goes directly to the controller.
The controller goes INTO one of the fused outputs.
The other fused outputs go to devices. (fans, lamps, etc. And that lighter plug)
There is only one wire pair to the battery. Most systems would be better with battery lugs instead of jumper cable clamps.
Each device or circuit has its own fuse, in the positive wire.
All the devices share a negative wire.
That fuse block, or 'fused distribution block', came from the auto parts store (Advanced Auto). The one shown has 6 circuits, one for the PV input, one for the lighter plug, and 4 more. I think there is one available (not here) with 8 fuses.
Fancy stereo retailers should have something similar at a higher price, because it's probably gold plated (really!). They commonly go from 2 to 12 fuses, and use uncommon or expensive fuses. (Pep-Boys has a few gold-plated choices accepting only expensive fuses)
They will need a "terminal block" and "matching jumpers" for the ground connections. Or a similar provision.
Some include the ground connections on the fuse-holder do-hickey. Easier and recommended if it's available. Worth the extra money.
This Example shows the fuse holder and the common ground/negative area,
http://www.cabelas.com/cabelas/en/templates/purchase/products-found.jsp?_requestid=53214
Solder all the crimp connectors to their wires.
Use anti-corrosion grease on the connector to fuse connection, and the fuse to block connection. (most of my stuff is installed in humid barns, so I know it helps)
G-