Testing of Minuteman launch facility flooded lead acid batteries for service life projection

Capacity performance tests were completed on 47 flooded lead-calcium batteries ranging from 5- to 23-years-old. These batteries had been maintained in the Minuteman missile silos on float charge over the majority of their life to provide emergency or secondary power. Capacity results showed no capacity degradation in the oldest batteries and cell dissections revealed only minor deterioration of the lead calcium grids. However, an increase in the cell float voltage range was observed in the 22-year-old batteries. Although signs of deterioration have begun, the solid capacity results indicate additional service life is still available. Additional data is also presented from on-going cycle tests being performed on a 5-and 21-year-old battery which supports the performance capability remaining in these aged batteries