Review on XYZ INVT 4000W Pure Sine Wave Inverter - 48V DC to 120V AC Surge 8000 Watt Power Converter Generator with 100ft Wireless Remote Control - Ideal for Solar Systems, Off-Grid Home Grid, Camping, RV (4000W 48V 120V) by Jim Kriegshauser

They seem to be keeping pace with their mainboard design. Good PR. But poor quality control. Bought this unit for a future project. After receiving it, I tested the device by applying 48V from BigBattery.com (Llama-LiFeP04-115Ah) for a few minutes. It started with no problems and seems to be working fine. Stored for over a year. During the build I ran the module; After 4 or 5 minutes it will beep and then turn off completely. I waited 30 seconds and repeated it again, and then it all repeated again. Since then it has been very unstable. Contact (by email) the company. very helpful. They told me they don't have service centers here in the US (I'm in Aziz). So no big help here! The problem appears to be a broken Darlington transistor (shown in area 5 in the figure). Probably from the manufacturer Zhengxinyuan Electronics (hk) Co. (of course in China). Once this Darlington transistor has warmed up - enough - a crack in the open case interacts with the oxygen, changing its output value and causing the device to turn off. The more you use it, the worse it gets. This will eventually cause the rest of the adjacent circuitry to fail, causing most of the MOSFET output to fail. Most likely this part (MJS122 041) was assembled by a robot. Without quality control (camera and laser inspection of the alignment of parts and good quality parts - IMOH). Most inverters are currently manufactured in China, Japan or Korea. Thanks to your American CEOs for that! When you buy an inverter or electronics; it must run continuously for at least 24 hours to check again. So you can return it; since you only have about three days to return it. And you have to return it. always! So now I'm stuck with a useless electronic piece for $626.97 (not cheap!). Don't trust most garages. Also, the lack of a circuit would imply some reverse engineering; something most stores don't have the time or staff training (or similar experience) for. You have neither the equipment to work nor the soldering skills for SMD. Too old for that (74 years old)! Years, months, days 1, 2, 29 = 455 full days (455-130 minus no work days) 325 actual work days