MPPT Breaker

You say to always connect the batteries before you connect the Solar panels. What happens if the breaker trips between the controller and the batteries and the panels are still connected? Will this damage the controller? Thanks

There is an ongoing debate about this, particularly focused around if the BMS disconnects the battery from the SCC (same thing). The general consensus is that nothing happens! Must admit, I connected my PV array before connecting my battery (because I didn't RTFM) and nothing happened. I think Will posted a video a while back about 'I cannot break my SCC' or something similar.

But I don't know the definitive answer.

Nothing happens because there is no complete circuit.

The only thing that "should" be done when connecting things is when connecting the battery to the inverter. Use a resistor to charge the capacitors to the inverter otherwise you get a pretty large arc.