Non-profit organization considers plug-in hybrid cars the wave of future

• CalCars calls its prototype the "Prius+" and boasts that the modified car can deliver upward of 100 miles per gallon under the right driving conditions.
• When a Prius driver brakes, the car's electric motor becomes a generator, creating electricity that is stored in a battery pack, which is later used by the electric motor.
• However, engineers like Ron Gremban, who volunteered to be the technical lead for the Prius+ Project, thought it might be more efficient to charge the Prius' batteries using power from the grid.
• Such a modification would allow Prius drivers to take local trips at low speeds using only battery power, without burning any gas at all.
• Once Gremban started investigating the possibility of a plug-in Prius, he discovered that the nickel metal hydride batteries that came with the 2004 model couldn't hold enough energy to get more than a few miles on electric-only mode.
• The new battery pack was able to deliver enough power to allow the car to accelerate comfortably to 34 miles an hour, the speed at which the Prius automatically engages its gas engine.
• Energy CS engineers and co-owners Greg Hanssen and Pete Nortman created a battery-management system that allows the car to operate in electric-only mode and deceives the car's main computer system, telling it that the batteries are very nearly full even when they are more than half empty.
• To maximize the life of the battery pack, Toyota engineers designed the Prius to keep the batteries about 60 percent charged.
• The Energy CS controller tells the main computer that the batteries are well above 60 percent full, so the system will draw more power from the batteries.
• EDrive's goal is to have a plug-in retrofit available to people in Southern California for about $10,000 by early 2006.