I would just tap off of the outlet behind the refrigerator - get an electrician to do it if you are not very familiar with 120V power - it is simple and the most efficient way to get what you need. Adding an additional inverter just adds another parasitic load to your battery bank. Also, no inverter should EVER be connected to the chassis starting battery as mentioned by the other posters. Starting batteries are built for immediate high current draw usage followed by being immediately recharged. They are not intended to be "deep discharged" by an inverter.