BFL WROTE
"-Mex, it's not always the panel output that counts. With 24v panel and 12v battery, the controller-battery path carries almost twice the amps the panel-controller path does, so ampacity requirement goes up."
MEX REPLIES
"Fusing from the battery is another thing altogether. A short can cause a fire. So a fuse must protect this side from the battery."
This was part of my original answer.
-In Theory-
A shorted controller can catch fire if the amperage potential is high enough to support it. Therefore logic dictates it would not be unwise to rate fuse failure just high enough to compensate for cloud edging surges.
