For the SP2-12000 testing, a fluorescent light near my work bench was flickering, so I wonder if I had some voltage drop. I was expecting the 12k to hold full power for closer to 4 seconds, but maybe my 240v 30A circuit is holding it back?
Also, just in case I wasn't very clear, that's with both channels running equally but I'm only measuring the voltage off a single channel. So all in all that amp was outputting a total of 12,000w RMS for 2.5 seconds, which is really close to factory specs.
That also means for 2.5 seconds the power supplies were outputting over 110A combined! For the last 4.5 seconds they were outputting over 70A, and I'm sure well before that point the capacitors were completely drained.