My Bluetti AC200P percent of charge shows puzzling changes.../..

[Zischang]

I have had this unit for about a year. Anyone know if I can estimate true percent of charge from a voltage display in the unit? What is strange is that the POC will suddenly jump from 60%-70% to 100% in just a very short time (like a couple of minutes). This with 400W coming in from solar panels. I also charge from scooter battery on cloudy days. Today Bluetti POC said 50% and I connected 42V 425 watt scooter battery (which I maintain at 80%) . In just 15 minutes the Bluetti said 100% and shut down charging. How could such a small imput (maybe 100 watts) raise the Bluetti POC by 50%? When I first noticed this phenomenon, called the BLuetti, and got lost in his explanation..... Am I missing somethin?