Can you elaborate? I'd love to get 150 joules out of a system I only put 100 joules in to...
That's the max charge and discharge rates. The battery capacity is a separate number. You can only discharge what you have in the battery.
Time is a factor. You have to charge for 1.5 hours to be able to pull in 1 hour (minus system losses)
A Watt is an SI unit defined as 1 joule/second, and is used for measure rate of energy usage/generation. So this system generates up to 100 joules/second, and can output up to 150 joules/second (until the stored energy is consumed).
The inverter can pull 150W out. That doesn't mean it does. His main load is a swamp cooler, which doesn't even seem to be using the inverter.