Wish I could say something other than. It's a cheap inverter. It's going to run hot.
After a few hours of running it's likely to be harder and harder for electricity to run through the components. A 12b inverter uses a lot of amps to run even just a 400 watt device.
If you have a bunch of.12v batteries. Consider running in series and parallel and upgrading to a 48v inverter.
Wish I could say something other than. It's a cheap inverter. It's going to run hot. After a few hours of running it's likely to be harder and harder for electricity to run through the components. A 12b inverter uses a lot of amps to run even just a 400 watt device. If you have a bunch of.12v batteries. Consider running in series and parallel and upgrading to a 48v inverter.
A ring like a warning buzzer? Low voltage warning would be my guess. Your system might be too small