Just base, I'm not update to latest version yet. It's using around 15% battery for just 10 mins. 
Discussion
This is really bizarre. 🤔
Happens to me, too, I just never thought much of it. I'm on GrapheneOS and try to be pretty tight with what I install and let run. Maybe some problematic relays in bad states or something?
It's a conflict with the rest of the spyware you have on your phone that causes Amethyst to behave in a buggy manner, crash a lot and use tons of battery. For me Amethyst runs super smoothly, never crashes, doesn't use a lot of battery; for others it's the opposite. The solution is to stop using phones.
I decide to use this phone, the battery can last at least a week :). 