Throw those jumper cables away. A sensor-and-software system under development at Stuttgart, Germany-based Bosch promises an end to weak or dead batteries, which account for one in seven car breakdowns. The unit, housed in a box the size of a deck of cards, monitors the battery’s ability to hold its charge and partially regulates power flows throughout the car. If the battery charge falls below a threshold level, for example, the system might raise the engine idle rate briefly to speed recharging or cut off power to low-priority systems such as heated seats, says Gnter Threin, an electrical engineer at Bosch who codeveloped the system. Using proprietary software that models the way batteries deteriorate with age, the system can warn a driver to replace the car battery well before the starter motor starts to struggle. An early version of the technology will be installed in some luxury car models this year; improved and lower-cost versions for wider applications are expected by 2005.