The rechargeable, vented nickel-cadmium storage batteries, cells, and components 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 emergency loads. Commercial batteries have a separate charger. These batteries, 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.