Why won't 2000w inverter run 900w microwave?

MP soldier wrote:
He put a 3 way switch in the camper (shore power/inverter/battery). Why won't this inverter power the microwave? Could it be too small gauge of wire from the inverter to micro?I have 2 six volt batteries fully charged.

I see several issues here.

2 batteries is a bare minimum (and often not enough) to run high-wattage devices like MW. How old are the batteries? Just because they're full charged doesn't mean they're in good enough shape to sustain a big discharge.

It's likely the wires from the batteries to the inverter are too small or too long. It's almost unheard of that the wire to the micro is too small - if it were it wouldn't run on shore power.Wayne might be thinking you said the wire from the battery to inverter.

Also, the switch.. depending on where that is in the circuit could be affecting performance.

To add insult to injury, that brand of inverter is not exactly top of the line...but I don't think it's your problem.

Read the label or the manual for the microwave oven.

It will tell you how much current (Amps) it draws. Multiply by 120 to determine the AC power drawn from the inverter.

The power rating on a microwave oven is the output power from the magnetron tube and they are only about 50% efficient.

I would go with 2g wire. JMO

Could it be too small gauge of wire from the inverter to micro?

That's the most likely reason. Measure the voltage at the inverter as the microwave shuts down, then do it again at the battery, and see how much you're losing in the wires.