powertrain, but also premiered a number of features and technologies that would later find their way onto more common GM models and other manufacturers' cars. The EV1 was among the first production vehicles to utilize aluminum in the construction of the frame. The car's body panels were made of plastic rather than metal, making the car lightweight and dent resistant. The vehicle was fitted with Anti-lock brakes and a traction control system. Comfort improvements included a keyless entry and ignition system, a special one-way thermal glass for better heat rejection on sunny days, an automated tire pressure loss warning system, electric power steering, and a time-programmable HVAC system. To boost efficiency, the EV1 possessed a very low and a . Super-light magnesium alloy wheels and seats provided strength despite their low weight, and self-sealing, low-rolling resistance tires developed by Michelin rounded out the EV1's exceptional efficiency characteristics. The EV1 was a subcompact car, with a 2-door coupé body style. Dimensions were in length, in width and in height. Drivetrain The car's 3-phase AC induction electric motor produced 137 brake horsepower (102 kW) at 7000 rpm. Like electric trains and all vehicles with an electric motor (and unlike a car powered by an internal combustion engine), the EV1 could deliver its full torque capacity throughout its power band, producing 110 pound-feet (149 newton-meters) of torque anywhere between 0 and 7000 rpm, allowing the omission of a manual or automatic gearbox. Power was delivered to the front wheels through a single-speed reduction integrated transmission. Battery The Gen I EV1 models, released in 1996, used lead–acid batteries, which weighed . The first batch of batteries were provided by GM's Delco Remy Division; these were rated at 53 amp-hours at 312 volts (16.5 kWh), and initially provided a range of per charge. The battery pack design, including the battery tray, electronic monitoring, safety disconnects, and crashworthiness, was utilized on all EV1 models and accommodated future (planned) energy storage products including NiMH and lithium-ion. Gen II cars, released in 1999, used a new batch of lead–acid batteries provided by Panasonic, which now weighed ; some Gen I cars were retrofitted with this battery pack. The Japanese batteries were rated at 60 amp-hours at 312 volts (18.7 kWh), and increased the EV1's range to . Soon after the rollout of the second-generation cars, the originally intended nickel–metal hydride (NiMH) "Ovonic" battery pack, which reduced the car's