Calculating watt hours?

I have the AC180. It has 1152 watt hours, but it only ran a 25watt lightbulb for 22 hours. Shouldn’t it run that for 46 hours? Or do I not understand how to calculate this? I am new to this technology.

The machine will have a certain no-load power consumption when it is turned on.

Have you ever tried to calibrate SOC?
First discharge the machine to 0%, then charge it to 100% via AC. During this time it needs to be charged continuously with no loaded.
Please try to cycle twice to see if the loading time will be improved.

It’s my understanding that at different loads the inverter efficiency is different.

I looked at a chart and it appears that at 25W that the AC inverter efficiency is approximately 50%.

So 1,152wh x .5 equals 576wh and 576wh ÷ 25w = 23 hrs.