An interior door does not have to withstand extreme weather changes. Interior and exterior doors are not the same product sold under different labels. The construction of each is different, with exterior doors given special treatment to stand up to the elements and frequent use.
The charging of lead-acid batteries can be hazardous. However, many workers may not see it that way since it is such a common activity in many workplaces. The two primary risks are from hydrogen gas formed when the battery is being charged and the sulfuric acid in the battery fluid.
The battery is a DC (direct current) device as it produces  unidirectional current flow.    A charger is a device that produces a DC voltage. We usually think  of this device as being plugged into an AC source (like a wall  outlet). The voltage it produces is slightly higher than that of  the battery it is designed to charge. All we need to do is hook the  charger up to the battery and the battery charges.