The storage batteries covered by this specification are used in fixed-wing and rotary-wing military aircraft. The batteries are used for starting engines or auxiliary power units. They also provide electricity to support aircraft emergency loads, aeronautical and ground systems, and associated equipment. Commercial batteries have a separate charger. Most of the batteries under this specification, however, are designed to be charged directly from the electrical bus without the use of a separate charger. The batteries are also exposed for prolonged periods to extreme seagoing environments not encountered by civilian aircraft.