More than 20 Dodge Sprinter Plug-in Hybrid Electric Vehicles (PHEV) will be in service in the United States between now and the first quarter of 2008 as part of a test-fleet program, according to DaimlerChrysler. DaimlerChrysler says it is the only auto manufacturer currently evaluating a variety of plug-in hybrid powertrain configurations under customer-operation conditions in real-world service. Battery development is one of the keys to the success of hybrid and fuel cell transportation, and lithium ion holds the greatest promise for battery technology, according to the company. A number of the Dodge Sprinter PHEVs are equipped with lithium-ion batteries, which are about half the weight and have much greater storage capacities when compared with nickel-metal hydride batteries. The vehicles will yield technical information through real world driving conditions about lifetime, performance and cost of batteries. Plug-in hybrid technology is part of DaimlerChrysler's advanced propulsion technology umbrella, which also includes exceptionally efficient gasoline engines, advanced diesel technology, ethanol flex-fuel and zero-emission fuel cell vehicles.