Can I leave a fully charged lithium-ion battery in an unplugged Fenix charger?Updated 3 hours ago

Storing a fully charged lithium-ion battery in an unplugged Fenix charger shouldn't be any problem; however, it's probably not the best practice. These batteries are very powerful and do require careful handling. It's recommended that you store them in a case that keeps the + and - terminals separated, since you don't want multiple loose batteries making contact terminal-to-terminal. Another reason not to leave a battery in the charger long-term: the constant spring pressure holding it in place can weaken the springs over time, which isn't good for the battery either.