Unless it's doesn't. Catastrophic failures of solar controllers are not unheard of. @mainsail posted about such events some time ago. Each time the failure resulted in significant damage to wiring and batteries. A power source should have OCP.The controller can only output as much as its internal components will let it, which is its rating. The cables should be sized to handle the maximum output current that can come from the controller. The batteries can output hundreds of amps, far more than the cables can handle. That’s why you fuse at the battery end of the cable.