Many battery energy-storage applications are currently undergoing a progressive change away from the traditional flooded lead-acid battery to a valve-regulated design which offers convenience both in operation (spill-proof, able to be rapidly recharged) and in reduced maintenance. At the same time, there are large changes in prospect in the applications themselves. In the transport sector, it appears that at least part of the largest of all present markets, the 12/14 V starting, lighting and ignition (SLI) battery, will be replaced by a 36/42 V system. Also, there may be some substitution of electric and/or hybrid electric vehicles for vehicles that employ internal combustion engines alone. There is also, currently, rapid growth in the use of valve-regulated lead-acid batteries for telecommunications and there is enormous potential for future growth in remote-area power supplies (RAPSs). The present paper reviews some of the salient aspects of the research and development programs that are being carried out in order to meet these challenges. (C) 2001 Elsevier Science B.V. All rights reserved.