Taming the dreaded 10s spark

[BrianG]

A triac has a ~0.7v drop so the power dissipated at ~20A would be 14w - not a small amount. Also, you would need quite a large triac to handle the 150A+ bursts without damage. If anything, a smaller triac could be used to get the caps charged up, then connect the main wires together (bypassing the triac) for running.

If you still want to go this route, I'd use a small bank of FETs to do the switching. That way, you can keep it in the circuit with minimal losses if you really want to use it while running.