Over the weekend, I purchased a 7.62 mm ammo box from the local military surplus store. The price was only $3.99 since the box was a little bit rusty and dented. It’s the perfect size for my 12 volt charging battery, and all my other batteries. The dent is even nice because it’s a vent in case the lipo batteries ignite. They also had .50 caliber ammo boxes for $14.99, but they were a bit too big for my needs.