Application of the sealed lead-acid battery on the Boeing 777

With the pressure for airlines to be profitable, maintenance costs are seen as an area where major savings can be made. Vented nickel cadmium and lead acid aircraft batteries have traditionally required frequent removal, for capacity tests, topping up and cycling. With the advent of sealed battery systems, the possibility of maintenance free operation or greatly reduced maintenance has become a reality. This paper shows how the unique characteristics of the Hawker Energy system have been utilised, in conjunction with a "smart" charger/monitoring system, to give a 5 year "No Maintenance" sealed Pb-acid secondary battery.<>