In September 2012 Chrysler temporarily suspended the demonstration program. All 109 Dodge Ram 1500 Plug-in Hybrids and 23 Chrysler Town & Country plug-in hybrids deployed by the program were recalled due to damage sustained by three separate pickup trucks when their 12.9 kWh battery packs overheated. The carmaker plans to upgrade the battery packs with cells that use different lithium-ion chemistry before the vehicles go back on service. Chrysler explained that no one was injured from any of the incidents, and the vehicles were not occupied at the time, nor any of the minivans were involved in any incident, but they were withdrawn as a precaution. The demonstration is a program jointly funded by Chrysler and the U.S. Department of Energy that includes the first-ever factory-produced vehicles capable of reverse power flow. The experimental system would allow fleet operators to use their plug-in hybrids to supply electricity for a building during a power outage, reduce power usage when electric rates are high, or even sell electricity back to their utility company. The company reported that the demonstration fleet had collectively accumulated 1.3 million miles (2.1 million km) before the vehicles were recalled. Chrysler also reported that the plug-in pickups delivered peak average fuel economy of , while the plug-in hybrid minivans delivered .