Inverter and battery sizing to power my camper microwave

Well, I’d note that there’s lots of connections in my smart-phone (2 billion transistors) and PSW inverter-charger, but when done properly, 2 inverters, 3 phones and 2 i-pads later, I’ve yet to have a single problem…Subject to change?? (I donno…)..Honestly, over the past many years I’ve yet to lose a moments sleep over these perceived boogieman - that some folks do, I can accept that…

3 tons