The best course of action would be to only use cells that you know the specifications of and stay within those parameters. I don’t know if you’ve seen pictures of what has happened to vape people who have pushed batteries too far, but the words permanent disfigurement come to mind. Even if not near your face you could still lose fingers and suffer pretty horrible burns. It’s not worth the risk when you can get nice Samsung, Sanyo, Panasonic, Sony etc. batteries that will meet your needs for $5-10 in most cases.