My catastrophic failure fuses are 350 amps each. My wire from the battery buss to the controller is not capable of sustaining 350 amps, so I would fuse to the wire size between the controller and the battery bank. The rule is "always fuse to the wire size".
In addition, since I have twin battery banks and switches to select where the solar harvest is sent, I have fused to protect the lovely switches that have led's in the stem. This approach worked to my favor when a technician managed to wire my system for 24 volts. I lost one Castrophic failure fuse, the reverse polarity fuses in the converter, and one of the fuses protecting the switch on that "leg".
Perhaps some one might consider this a belt and suspenders approach, but it paid off *big time* for me.
2oldman wrote:
If I have a catastrophe fuse on the battery +, why do I need one on the controller wire to the buss/battery?
