I've heard about hat they can be replaced with Thill bobber lights but haven't been able to confirm this. Anyone else have an idea?

I used to make my own lighted nocks with tills bobber lights but don't own any nockturnals so i can tell you

Interesting question do you know the battery's life expectancy if never illuminated?

I have one laying out on the porch, it was full of blood so I took it off of arrow and left it on. its still shining , been on for a week so far. not as bright though. much easier to get a new one.

My buddy found one of his 10 days after he shot it, still glowing. A landowner where I hunt found one, put in his garage and 30 days later it still was lit. Wasn't mine.