I'm running the same Giandel 2000/4000 inverter with a MOES ATS and had the same OL experience in less than 6 months. I hope your replacement inverter fares better than your first.
Whoa, that looks like a pretty good deal for Lifepo4 cells. I've heard that it's important to check if the cells are actually new instead of grade B or used. Do you know if the link you shared is for new cells?