Can1500w inverter or Honda 2k gen work 900w Microwave

My Honda Eu200i runs my microwave. I always turn off the eco switch first so the generator ramps up. Many times the starting surge slows the microwave down momentarily, but it comes back up fairly quickly. Sometimes I turn off the charge controller so I'm not trying to power the batteries at the same time as the microwave.

I've been able to run mine while the Honda 2k powers it. In fact, I had to tell the DW to let the generator run for a minute before slapping the MW on. I had to explain to her the generator needs a minute to warm up. She literally pressed the ON button just as the generator fired.

I have never tried an inverter.

It may depend on other thigns.
My Inverter was 2000 watts not sure of the Dometic/LG microwave. CDMW12
Ok now sure
Power 1100 watts
Rated consumption 1500 Watts

My 2000 watt inverter needed FULL batteries to Well make a less than 1000 watt cup of coffee. .But it ran the microwave fairly.

You have a 900 watt or about 82% (81 and change)
81 (and change) Percent of 1500 is 1227 and change

That is close But the Honda should take it provided, once againg the batteries are FULL or the converter is OFF.

MY brother travels alone and only uses the microwave to cook or defrost for s hort time. He only drains the 200amp bank about 50amps max and he has 400watts of solar which usually recharges the batteries.
Again, I will see him tomorrow at the campground and give it a full checkout. I think his microwave has his inverte overloaded and cutting out because of it. He called GoPower today but hasn't returned my call yet.

Whether the inverter can power your brother's microwave is one matter, the toll to 2 batteries for just a few minutes of microwave use will take a significant bite out of the onboard 12 volt reserves. This will eventually lead to powering up the genny earlier and longer to replenish consumed amphours, our inverter could power up our microwave but I always would run the genny since it would literally zap our 2 battery setup.

We have plenty of solar which helps, inevitably when using high amperage items (microwave, blow dryer, curling irons, coffee makers, blenders, etc.) on just a dual battery bank the generator ends up being used more than necessary. We have an Iota IQ4 smart converter that quickly restores our batteries during bulk charging, having a remote start genny (Onan/Champion 3100) makes it easy for us to use high amp items at our convenience.

genny yes.
inverter depends
1) what size battery cables and how long the run from battery(s) to inverter
2) what size and number of batteries
3) battery state of charge.
4) inverter max continous rated VA

My brother says he has 2awg cable going from inverter to 2 BB Lithium batteries. He is calling GoPower today as he bought their inverter with their recommendation. He says all testing has been done directly with isolated circuits soley the microwave. If he can get the inverter to handle the load, then he can alway use it that way instead of using the microwave.
I will be camping with him tomorrow and will bring all my test equipment like clamp-on ammeter, Kill-a-watt and short power cored with exposed wiring for clamp-on use.

I run my micro on my Honda 2000. You can hear the sound of it slow initially on startup while the genny ramps up speed to keep up with the load, but it works fine.
I run it in Econo mode so it doesnt always rev so high.
I don't know how many watts mine is, never checked. It came with the TT.

The short answer is yes. I constantly run my microwave with one EU2000i generator. Of course, it depends on what else is running. Maybe the reason his inverter won't power the microwave is that things are running that he has either forgot about or doesn't realize they are powered by the inverter?

How many batteries does Brother have connected to the inverter w/o and what size wire, mucho battery capacity is king when it comes to this situation,with Big Thick Cables, for the high amps
I consider a 1500w inverter not large enough for a 1300x load, doesn't allow for sufficient overhead for inverter conversion loss 15% need 1495watts into the inverter from the batteries, and that doses not include startup surge spike