If at the time of power cut, your inverter starts beeping and then it shuts down, it usually happens when there is a heavy load on the inverter. Make sure that there are no heavy load appliances in use. Example – Iron, AC, Refrigerator, etc. If there is no heavy load appliance in use and it is still beeping, check the water level of the battery. If the problem is still not solved, your inverter battery might have failed.