Lexus LS600h LED Low-Beam Headlight

The average electric vehicle's battery pack has the energy equivalent of only 1-2 gallons of gas. If you had that much in your IC vehicle, you'd be looking for a gas station right about now. However, since electric motors are much more efficient than internal combustion engines, a decent range can still be obtained from these battery packs. One downside to going farther on less energy is that accessories such as lighting are about 10 times more detrimental to your range than they would be on a gasoline vehicle.

Jonathan Dunlap, the automotive lighting engineer and product marketing manager with OSRAM SYLVANIA, says that LED (light emitting diode) lighting can have a significant impact on an electric vehicle's range. Over only that last 2-3 years, the efficiency of LEDs has increased to the point where LEDs use less than 25% the energy of halogen bulbs (and this will only get better in the coming years). So, how much extra range can an EV get by using today's LED headlights? According to Dunlap:

An efficient LED headlamp system can extend vehicle range by nearly six miles (9.5 km). Even with conventional vehicles, a 28 watt LED system emits only 196 grams of carbon dioxide per 100 kilometers compared to 768 grams of carbon dioxide per 100 kilometers from conventional 110 watt H7 halogen bulbs.
LEDs have additional benefits such as extremely long life (50,000 hours is not uncommon) and vibration tolerance, meaning they can last the life of the car. The main hurdle at this point is getting upfront costs down.

[Source: OSRAM]