I have been running a frost free, home sized refridge on Irish Ayes for about 3 years. When we are on the inverter, a Heart 25, it chews a few more amps than when not defrosting, but not all that much. My Heart 25, with 4 six -volt deep cycle batteries that are dedicated to the inverter handles all the load I put on it for 12 hours easily, and usually more. Mike M/V Irish Ayes Gulfstar 44 Knoxville, TN