From a practical standpoint; they’re ultra-bright and theoretically will last an extremely long time. They also draw less power than a typical halogen bulb; our H4 kit is advertised at consuming 1.4 amps as opposed to 5 amps sucked up by a halogen bulb.
On one hand; who cares, your car was obviously designed to run with whatever draw your factory headlights had. On the other this takes some tax off your electrical system and might help your battery last longer. Especially if you’re running extra accessories like a fridge or a disco ball or a bitchin’ car stereo.
LED headlights throw extremely intense light with very little draw on your car’s electrical system. Now that they’re trickling down to the aftermarket, you can buy a simple plug-in “LED retrofit kit” that straight swaps your halogen bulbs. We installed a set to see if that’s actually a good idea.
Our trusty Typical Old Car is a 1996 Toyota 4Runner, which uses very common “H4” sized halogen headlight bulbs. It’s also got the wide-open eyes of an anime animal for light housings, which should give us a good indication of how the LEDs use a pre-LED car’s reflective bits.
Intensity of brightness is one thing but in order to really toss light way down the road your LED will have to bounce it through your stock headlight housing just as well as a halogen.
To see why that might be a concern, just take a look at the LED unit itself.
While a halogen bulb is inherently omnidirectional, LEDs only project from those tiny little points (diodes.) The units in our kit have four little diodes a piece, which increase from extremely bright on the low-beam setting to retina-cleansing on the high-beam setting.