In article ,
"Dave Plowman (News)" writes:
In article ,
Andy Burns wrote:
that 400w includes headlights. And very few cars have LED ones. HID
are more common - and vastly more efficient than tungsten. My 35 watt
units produce much more light than 55w halogen. I'm not sure how LED
compares to that.

The top-end Audis have optional LED headlights, it mentions 40W per unit
for the dipped beam, but doesn't state the wattage for high-beam.

That's more or less the same as HID. Be interesting to do a comparison.
I'm very happy with my HID units.

The only snags with HID is the time they take to reach full brightness,
and not being a good idea to flash them, like all such types. Not a
problem in practice, but means you can't switch them on and off like
'normal' units. So you either use mirrors for dip/main beam or add
conventional mains. And some other lamps for flashing.

I suspect LED will prove cheaper, rather than better, in the scheme of
things.

HIDs are cheap to make and factory fit and increase the perceived
value of the car, which makes for a good manufacturer profit margin.
Also good profit on spare parts.

LEDs are still expensive to design and manufacture for the required
performance, and don't add much (if any) perceived value over HID,
so not yet so compelling for manufacturers. It will probably come
in time though, particularly as efficiency isn't a significant
factor in this application (high efficiency jacks up LED price).

LED would perhaps allow for some clever stuff with dynamic cut-off
adjustments, such as automatic left/right side dipping based on
GPS (country, and even road-specific, e.g. where there can't be
any oncoming traffic). If the French still required yellow
headlamps, I could imagine some adjustable colour versions
too (again, derived from the GPS location).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]