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1.0 The aircraft industry demands high power batteries for auxiliary power unit (APU) and engine start. The power demands for these applications are met lead acid battery, however, these batteries are bulky and heavy. One of the important criteria for selecting an aircraft battery is its weight. There is an acute need for a lead acid battery, which can supply the power and energy demands of the application but also be lightweight. In this paper we present the use of lead coated Aluminum (Al) grids which result in a lightweight lead acid battery. The battery with lead (Pb) coated Al grids are 15% lighter in weight when compared to conventional lead acid battery. The results on capacity, high rate and cycle life of batteries made from lead coated Al grids is presented and discussed in detail in this paper.

Historically, Transformer Rectifiers Units (TRUs) have been unregulated devices used to provide 28-Volt Direct Current (vdc) power on 400 Hertz, 115-Volt Alternating Current (vac) aircraft. By design, a TRU produces an unregulated voltage output that varies with current (load) required by utilization equipment on the 28-Volt Buss. This TRU voltage output variation typically ranges from 30-31 volts (at no load) down to 24 volts (at 100%load) under stable input conditions. AC transients, in combination with sudden or heavy DC loads, can cause a typical TRU voltage output to fall into the 17-18 volt range or even lower. Modern aircraft are experiencing three trends which are impacted by older TRU characteristics. The first is that airframes are being used for longer periods of time; scheduled use is being increased to avoid the budget constraints of replacing costly airframes.