Now when power goes out (a frequent event in the mountains of Eastern Kentucky), the UPS keeps things running long enough to pull lead acid batteries off the charging station and plug the UPS into the inverter with no loss of up time

so I know all the batteries are not the problem

Very good sine power inverter, used with the remote to build a portable battery box does not seem to overheat produces accurate voltage.

Hooked up a 1500 watt hair dryer unit went instantly into alarm condition was running it with a 12v lithium iron phosphate battery pack capable of delivering 5000 watts of power