Charging Lithium Batteries: The Basics

We charge our aircraft lithium polymer batteries indoors inside a fire proof steel tool cabinet which holds the intelligent chargers. Next to the station is a bucket of sand, and by the door, a fire extinguisher. Why not charge outside? Because students are present and we can't control that environment nor monitor the batteries. From experience, if a battery is about to fail, it will get hot, so we check them every few minutes to ensure they stay at room temperature. Sometimes, you will also hea