Fuse the wire from the battery to controller, and size that wire correctly. I do not fuse the panel
wiring. ('cause if the fuse is rated for something around Imp, and it shorts, all your gonna get is Imp anyway and the fuse won't blow)
I feed my solar into my panel through a breaker in the panel. Was the easiest way to do it. But I've only got 160W of solar on the
boat. And my panel is 3 feet from my batteries.
I've got the 30A Midnight kid in my motorhome and it's a fantastic solar controller. The MPPT tracks great, the battery charge profile is perfect, etc.... Too bad I've got a crap PWM in the
boat.
Interesting all the don't hook up panels without the battery comments. I'll bet dollars to doughnuts that a Midnight Solar controller won't blow up without a battery connected. After all, what happens if the fuse blows? My
cheap PWM controller gets switched off all the time. It hasn't blown up either. If I designed a buck converter circuit that would fry itself in that situation (input but no load)... well... I don't know.. But I wouldn't be proud of it.