Protect the wiring is job 1
Unless somone botched the panel installation the panel to controller wire size is WAY bigger because of avoiding voltage drop. So you short panel output 'till the cows come home and the wire will laugh at it.
Fusing from the battery is another thing altogether. A short can cause a fire. So a fuse must protect this side from the battery.
But basically it is ignorance pure and simple to fit fuses rated way about array output potential.
Some "tech writers" can't count past ten without unzipping their pants. Common sense should be your way point not hare-brained theory from a pimple-faced kid.
