How do I safely switch high current from OFF state to: CHARGING or LOAD state between high current battery and load (BLDC motor) without catching fire? I think that the current might peak at 15A. Can I control the switching with mosfets? what about solid state relays? Could something like DFR0457 work?
Post links to technical information on all of the hardware and links to technical information on them. Depending on the type of motor etc I would expect a peak of about 50 amps, it is entirely dependent on the motor and its load. You would be seeing something in the range of 1,800 watts for the peak and that can and does destroy switches etc. Railroader has given you some great advice please follow it. If not do not expect much more from us.