The attributes which are essential for a battery to be successful as the en
ergy store for an electric vehicle are reviewed. These are then matched aga
inst the substantial advances in the technology of valve-regulated lead-aci
d (VRLA) batteries that have been posted during the course of the technical
programme of the Advanced Lead-Acid Battery Consortium (ALABC). A project
which was designed to draw together several desirable features, identified
during the early years of the ALABC programme, into a test battery has prov
ided much useful information. The design target for specific energy (36 W h
kg(-1)) has been achieved successfully. Cycle-life is short, but it appear
s likely that an inappropriate charging regime with an unrestricted charge
factor was largely responsible. Benchmark tests with a commercial product a
lso yield very short life with this regime, but provide good performance wh
en the charge factor is kept in check. Attention to the deployment of suita
ble charging regimes continues to be a fruitful area in extending the life
of VRLA batteries, and the ALABC's programme to enhance both specific energ
y and life, while shortening recharge time, is making good progress. (C) 19
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