Do LED headlights increase EV miles?

No, headlights = about 100 watts, A.C. around 2,000 watts, heater around 7,000 watts, car up to 111,000 watts (maybe 10,000 to 20,000 watts average), so the lights are less than 1%. Not sure that LEDs are much more efficient for headlights anyway, maybe slightly. Pretend you save 20 watts it would increase range maybe 0.1%, which would be inside your measurement error.

Just to add, here is a great study that addresses this for gas and electric cars.
https://deepblue.lib.umich.edu/handle/2027.42/61187?show=full
They mention in current cars, LED low beams use basically the same power as Halogen low beams, and high beams about 60%.

You don't have 8x efficiency in current LED car lights. I also think they might be brighter than same wattage halogen so you might have better lighting, so maybe 2x or a bit better efficiency?

Edit, this study is a little old but point stands. However, maybe car LEDs are approaching 8x by now? Anyway, even if your LEDs used no power, the savings would be around 1% or 2% at best. Worthwhile considering an entire fleet, but not going to extend your range significantly.

One more thing to add, I know you realize that they are illegal to use, likely because they are brighter than halogen by watt. If they are 4x efficiency, that means a 30w LED is putting out more than twice the light (making them look favorable in comparisons). This is like using offroad 120 watt halogens or brighter. Be sure to test it by someone else driving past you in the Volt to see what you are inflicting on other drivers. Overly bright headlights are a safety hazard for other cars, however, they might not be terrible depending on reflector design.

sduck said:

How do HIDs compare to LEDs, and similarly to OEMs? I recently upgraded to HIDs from Diode Dynamics (the 35W 6K kit). Didn't do a ton of research, but it was an easy install, they provide much better light, and doesn't seem to be bothering oncoming drivers - at least I haven't been flashed yet.

Click to expand...

My understanding with HID is that they are more efficient than Halogen, maybe somewhere between LED and Halogen, but do have some warm up time (less than 1 minute) before they reach full brightness and bulbs won't last as long.