Theoretically it looks good but YMMV
300 A/H of battery @ 12v = 3.6KVA
300 watt hours of load x 5 = 1.5KVA
I have never seen one of these UPS deals that actually approached the theoretical time they should run. There is some loss in the inverter and you really need to know what the discharge rate was used to get the 150 A/H for the battery
