Leslie...I'll jump in if I may. Microwaves on board can be powered by batteries but you need an inverter
to convert the 12V to 120V AC. The small microwaves are generally around 700 watts which means you need an inverter
capable of supplying about 1500 watts due to start up power required.
700 watts will draw roughly 60 amps from your battery bank so you will use about 1 amp hour of your battery capacity for each MINUTE you run the oven
. Figure 2 amps to compensate for conversion losses and wiring and you will run a standard group 27 or 31 battery down to 1/2 capacity in about 25 minutes of running time. SO...if you want a microwave...make sure you have enough battery capacity in addition to the inverter
The other choice away from the dock is to buy a portable Honda type generator and plug the microwave into that.
Hope that is helpful.