How to get time of character

In plugin
How to get the character’s in-game time (to calculate exp ratio time 100%, 50%)

You can track when a char joins the game with joined_game() and calcualte in game time from there/

also exp ratio is returned in get_character_data()

Is there any way to know specifically how many hours of 100% exp are left?

Not without parsing the packet. I don’t keep track of that info.