It does not appear that I'll have any success with retrofitting an energy management system that is more sophisticated than a 10 amp auto reset circuit breaker.
I'm locked in to pure sine wave because I love induction cookers.
It may be that my attempts to force load support to do voltage support were more than the Magnum could handle. One day I was using 64 amps from the battery bank to keep the voltage in the campground at 106.x That went on for several hours. Of course when the air was turned off the Magnum then "went to town" on charging the battery bank.
My best case scenario is that Magnum will replace the unit.
Next best case is having it refurbished.
I wonder if there is a way to find out mean time between failure of the various quality inverters, Magnum, Victron, and Outback?