X2 on the battery disconnect switch. Several years ago my bride and I were returning home in the wee hours and came upon a nice 40ish street rod on fire. I had my extinguisher and put the fire out 2 or 3 times before the extinguisher was drained. Each time the fire reignited because he had a dead short and the battery cable was way too hot to remove it. Nothing to do but watch it burn to the ground. That convinced me and I installed a disconnect solenoid like a ford starter solenoid in the battery feed to the harness. Whenever the ignition switch was turned off, everything in the car went dead. It worked for me.
