The effects of lead sulfate on new sealed lead acid batteries

Emergency Medical Services (EMS) rely on batteries to power external cardia c defibrillators, While maintenance protocols should be followed to ensure that batteries possess adequate capacity to power their defibrillator, they are not often applied to new batteries, This study examines the effects of prolonged storage on sealed lead acid (SLA) batteries, the number of batte ries that are affected by lead sulfate, and the ability of a protocol to re store the capacity in SLA batteries. A prospective cohort of new batteries was subjected to testing and discharge protocols. Initial battery capacitie s were measured using a battery analyzer, An "over-discharge" protocol full y discharged the battery over a 24-h period, and batteries were recharged a nd reanalyzed, Capacity measurements were repeated twice, Sulfate buildup w as defined a priori as final capacity measurements greater than predischarg e measurements. There were 126 batteries studied, a mean of 14 months after manufacture. Overall, 47 batteries (36.5%) had measured capacity that was insufficient (<65% capacity). Batteries possessing very low initial capacit ies (<55%) responded with a significant improvement on average of 54.7% com pared with batteries within a normal capacity range (>65%) whose average im provement was 9.3%. After discharge, there was an average of 17% improvemen t in the measured capacity, with no differences in the final capacity readi ngs in each battery type. In conclusion, sealed lead acid batteries are aff ected by prolonged storage. The loss of capacity created by accumulation of lead sulfate can be reversed if battery maintenance protocols are used as part of EMS quality assurance programs. (C) 2000 Elsevier Science Inc.