I gave my friend a small apartment fridge out of our rv, we replaced it with a freezer so the fridge runs fine. She has a 1500 watt pure sine wave inverter, 200 am hours of lithium batteries and 400watts of solar. The fridge in my rv was powered by a 1000watt inverter and was never an issue but when she uses it, it randomly kicks the inverter off. Any ideas what I should check for her?