This paper reports experimental results of engine starting trials conducted by the Army on common military vehicles using capacitor power sources. Improved starting performance can be obtained with the use of a capacitor, particularly at low temperatures. Power delivered by battery-capacitor systems are presented and compared to battery-only systems. Weight, volume, life, and cost comparisons for the two systems are given. A preliminary life-of-system cost analysis is presented and shows the potential for substantial cost savings to the Army from the use of capacitors in its vehicles.