watts, volts, amps......need a bit of help

What do you plan on doing drawing a bunch of current for an extended period of time? Inverters do have over voltage shutdowns.

 

A fair comparison: Cooking a meal in the 1000w micro for 5 minutes is roughly equivalent to cranking your starter without the engine starting for 5 minutes. Your starting batteries were not designed to do that.

 

I'm no expert on all the ohms law and all, but I have a 1500 inverter in my truck and I run a 115v fridge, a microwave and a tv off of it for over 2 years now no problems. When I stop and use the microwave, I run the truck just to be sure I'm not drawing anything from the battery. You will be fine.

 

Ohms law is volts x amps = watts.
You loose a little amperage from heat and if you do not have oversize cables it will not work properly but a 1500W divided by 12 volts is 125 amps from the battery and the starter draws about 600 amp or better.