I’ve got a busy couple of days, but I managed to do an AC discharge test with a 60W incan bulb. Total capacity was 101.32Wh. I still have to discharge the battery to find out the true efficiency.
One thing that was a bit of a disappointment was the decline in AC voltage during the test. The original Omnicharge didn’t exhibit this. The Ultimate started out at 230V unloaded and dropped down to 213V after turning on the bulb. Just before cutting out the power the voltage had dropped to 198V. With an incan bulb this means a significant decrease in light output over the battery life. With universal voltage SMPS devices this doesn’t matter though and I would rarely use anything with a linear PSU with the powerbank.
The battery voltage was 3.2V (19.14V/6) when empty (had some time to bounce back though) so they are pretty conservative with the LVP.