For the price of a mid-range Android phone, [Kenneth Finnegan] turned a 50 caliber ammo can into a 50 amp-hour portable power supply. The battery pack uses four 3.5 V LiFePO 4 cells wired in ...

To ruggedize his build a little, he put it in a 50 caliber ammo can making it more ... features built-in to the computer PSU, so this ammo box power supply is still protected from short circuits ...