As said its all about battery capacity. If it works at all, ever, your inverter is doing what it should. What perplexes me, is the residential refrigerator is a known power hog. Most of the larger motorhomes using them, have dedicated battery's that run only the refrigerator. Trying to run a residential refrigerator off existing two or even four house battery's already running the entire motorhome, is a guarantee of a short run before the battery's go flat.
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