my whole life evolved about electricity,
"The cleaning lady tried to use the iron, and blew both the inverter and batteries."
something wroing, an iron draws about 1kw
either there was something else plugged and or a short circuit and there was no adecuate protection, no circuit breakers, or too large for the inverter
that is what ciircuit breakers are for, to break the flow of current if too much is being drawn, before burning...
"I called Trace and they told me..."
what do they know? LOL, unless you make sure you talk to a real experienced service person, never to a sales person..., or service desk line answered by low paid persons who knows from where, India has been my experience, all they do is read preset answers from a computer screen LOL
12v dc fridge and 120 ac fridge is the same thing as power consumption is concerned.... IF the size/btu rating is the same, they mainly say cubic feet, which does not tell you anything about consumption, but you can always figure it out, or read the sticker on the back
12v dc appliances are usually smaller, less consumption, as they are for boats and campers
12v dc appliances are usully more expensive as there is no demand for them