I got careless with my charging station and left a bank of rechargeable AA batteries plugged in for the weekend while we were away and came home to a house that reeked of wood smoke. My charging station is wood and one bad battery got really hot and melted the battery holder and burned into the wood but luckily it didn't ignite. I had been warned about battery fires online and always thought they must have been using chargers that weren't compatible and sort of blew it off. Everything I had was compatible so it's a real thing. Just a warning , it really does happen.