Specifications include, but are not limited to: It is the intent of these specifications to describe the minimum acceptable standards for obtaining EnerDel lithium-ion bus batteries, part no. PP320-689-C Vigor+ ESS (formerly PPA300-689), or approved equal. The specifications are not intended to limit competition, but to ensure that only quality products are received. King County is sourcing an alternative source for batteries used in the Allison EP 40/50 Energy Storage System (ESS). This will allow King County to replace the current nickel metal hydride (NiMH) batteries with lithium-ion batteries in the current New Flyer Allison Hybrid System and in future hybrid fleets in order to deliver longer life, higher reliability and better performance. The battery must be bid as a complete ESS system ready to connect to the Allison unit. The ESS is comprised of 240 NiMH modules separated into six (6) subpacks and three (3) parallel substrings. Each substring contains two (2) subpacks, a fuse, a low side-relay, a high side relay, a pre-charge relay, and a pre charge resistor. Each subpack contains 40 NiMH modules that are monitored by a Battery Control Interface Module (BCIM). The BCIM controls the fan speed, relay control, and monitors ESS parameters including temperature and power throughput.