At my hackerspace we charge our 18650 cells inside those green ammo boxes. Battery lockboxes are a way to stay pretty safe, even if a li-on, li-po, or lead acid

At my hackerspace we charge our 18650 cells inside those green ammo boxes. Battery lockboxes are a way to stay pretty safe, even if a li-on, li-po, or lead acid battery explodes, in a steel box it can't do so much. Obviously, doesn't help without removable batteries, which are more common on ebikes.