Mechanical Mod Fuse The Fuse goes between the mod and the negative side of your 18xxx sized battery. It is installed nipple UP on the bottom (negative) of your battery. The size of the unit is 3.69mm high and18.39mm wide. Due to the extra length it will add to your battery we can not guarantee it will work in all units. The 7 amp fuse is for use in most mechanical and other mods. It is particularly suited for mechanicals with no circuitry protection.
With lithium batteries one of the biggest safety issues can come from a hard short. The fuse is a mechanical fuse that will trip if it senses a short in the mod by breaking the connection to the battery.