As fuel costs and anti-idling legislation become more prevalent, the life cycle cost of the energy storage component of no-idle systems is becoming a critical consideration. Current systems employ up to four AGM lead-acid batteries, with a one year standard warranty. OEMs have reported higher than acceptable warranty claim levels and are interested in examining the potential advantages of alternative storage technologies. The use lead-carbon asymmetric hybrid battery/supercapacitor energy storage in the no-idle system application is examined through modified SAE J2185 cycle testing and other means - as these battery products have significantly improved rechargeability (charge acceptance) and longer life (up to 4x higher cycle life in deep cycle applications). The performance improvement is expected to provide shorter recharge times and reduced warranty claims. The technology could potentially offer means to a lower capacity alternator, thus reducing cost.