LED car headlights are a promising technology. They have many advantages over filament bulbs (longer life, faster on/off times, lower power consumption) but the technology has still limitations. LEDs can be used as car headlight when the lighting system is specifically designed for LEDs. There are even some DIY projects for this.
The current LED products do not not seem to be ready for drop-on replacement of normal light bulbs used on card headlight. Generally LED bulbs are generally not as bright as standard incandescent bulbs. This is a common problems on many LED products: they consume less power and have higher efficiency, but majority of the LED bulb replacement products have considerably less brightness than the original bulb they try to replace. Also the light is distributed differently so they can appear brighter in some applications and not as bright in others, it depends on the size and shape of the bulb housing and reflector. LED bulbs may cause some newer vehicles to indicate a bulb is burnt out (because of their low power consumption).
H1 68 x 1210 3.4W White Light Bulb (DC 12V) bulb promises a lot: Increased more visibility when driving at night. Easy installation, plug and play with no modification needed. Too bad the beam focus will be a floodlight! The reason for that is that H1 filament is about 1/32″ by 1/4″ and the light reflector optics are designed to produce the intended light beam from that kind of light source. If you replace the small filament type light source with a rod covered with LED’s the resulting light beam be a mess: light everywhere, but not focused. Not what was intended by the original car light designer. And not what the car lamp approval bodies expect the get out from the lamp.
Also the total light output would not be what is needed. most probably “not enough”. A 55w halogen should typically be putting out 500-1000 lumens (maybe more), whereas a good 3.4w led would be about 250 lumens or maybe even less. So you would get considerably less light out output that you would get with the original light bulb and the light beam would be a mess.
H7 6W 190-Lumen 18×5050 SMD LED Car White Light Bulb (DC 12V) is another bulb replacement product. It seems to have also same problems as the previous product. An ordinary halogen reaches an excess of 1000 lumen, as you can see, this led is only 190 lumens. This could maybe used for decorative “day lights” but cannot replace the main lights. The light output would probably be also mess. So the end result would be that installing such bulb to your car would get you very dim lights that would probably not meet the regulations covering the car headlight performance.
Maybe it is not so good idea to replace the car light bulb with LED yet. LED replacement product promise a lot but usually do not live up to their promises. If anyone knows any real LED alternatives to card bulbs, feel free to post comments on them.