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Adaptive Headlights



 
 
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  #21  
Old September 19th 06, 11:41 PM posted to alt.autos.bmw
Richard Sexton
external usenet poster
 
Posts: 285
Default Adaptive Headlights

In article >,
Dave Plowman (News) > wrote:
>In article >,
> Richard Sexton > wrote:
>> >Currently, the most efficient HID lamps do look blue compared to
>> >halogen. But are in fact closer to daylight.

>
>> Daylight is blue.

>
>No it's not. By definition.


Daylight is only not-blue at the equator.

>> The sky is blue not yellow.

>
>So the sun is blue? That's what provides daylight - not the sky.


The sky is blue becuse of scattering of light rays which reflect the
blue end of the spectrum.


--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
633CSi 250SE/C 300SD | http://aquaria.net http://killi.net
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  #22  
Old September 20th 06, 05:51 PM posted to alt.autos.bmw
Dave Plowman (News)
external usenet poster
 
Posts: 1,533
Default Adaptive Headlights

In article >,
Richard Sexton > wrote:
> >> That's pretty naive in my opinion.

> >
> >Really?


> Really. That's my opinion. It's not a fact and reasonable people disagree
> all the time. I'm listening.


I'm not objecting to you disagreeing - merely objecting to you calling my
opinion naive. Which suggests I haven't given it any thought or know
nothing about lighting.

> >> Nothing could be easier than incandescents. You apply voltage to two
> >> pins and they make light. They're cheap.

> >
> >Well just about everything on a car has moved on with improving
> >technology. Or perhaps you want to go back to points ignition? That's
> >cheap too. As is a nice single downdraught carb.


> No. We're talking about lights here.


But the 'simple and cheap' arguments are often put forward in favour of
points and carbs. And those who do simply ignore efficiency.

> >> HIDs ARE great, but, they have a lot of problems with automotive
> >> applications: they don't come on instanly and a lot has to be done to
> >> get around this.

> >
> >Err, how often does it get dark suddenly? I've never found the time they
> >take to get to full output a problem.


> Well, YOU haven't had a problem but the fact remains, with incandescents
> when you turn on the switch you get full brightness immediately. There's
> a non-zero chance this will be a problem somewhere sometime.


Again why? Many cars still have incandescent main beams. For signalling
purposes if nothing else. No reason why they couldn't be incorporated into
a main beam HID setup for just this reason.

> >> They require weird voltages and an extra large striking
> >> voltage. They're expensive and complicated.

> >
> >They *sell* for much more. But then so does everything when it's new.


> I know why, I'm just pointing out it falls in the "con" not "pro" column.


> >> They are however more efficient so you get the same light from less
> >> voltage and that's important.

> >
> >Actually, less current.


> True. Less energy what what I meat to say and module some teenager
> pranging in my ear I actually might have.


> >> They're not THAT much brighter, they just look brighter
> >> because of the color of the light.

> >
> >They produce approximately three times the light for the same current -
> >not difficult since incandescent lamps are incredibly inefficient.


> Understood, but incandcents, using more energy yield very close to
> the same light, and advanced ones lke CSR's put out more light than
> HIDs.


The light output of any lamp can be increased or decreased. Saying you can
already buy an 150 watt H7 incandescent but only a 35 watt HID is pretty
meaningless in the scale of things. However, upping the wattage of an
incandescent can often result in reflector or lens damage due to heat. And
voltage drop in the wiring etc can also cause problems.

> >For things like tail lights etc you don't need omni directional
> >radiation - indeed this just means you have to add some form of
> >reflector.


> No and no. You need to check lighting regulations and yo're guessing
> (wrongly) about the reflector.


The reflector behind a incandescent lamp in say an indicator or tail light
- not a passive reflector needed for safety. Because ordinary incandescent
bulbs have a near omnidirectional beam pattern, some form of crude
reflector is needed to increase the efficiency. Not so with an LED type
where the lens is built in.

> >For many applications around the car, filament or point source lamps
> >are anything but ideal. Interior lighting for example would be better
> >with large soft sources. As would most other lights apart from
> >headlamps. We're simply used to filament lamps - that's all.


> Well, I've tried LED's inside. Worthless. You go try it ane lemme know
> what you think. Luxeons are nice ones to play with.


LED technology has a long way to go - as with much else in lighting. But
the sure thing is the tungsten filament bulb's days are numbered.

--
*If love is blind, why is lingerie so popular? *

Dave Plowman London SW
To e-mail, change noise into sound.
  #23  
Old September 20th 06, 06:05 PM posted to alt.autos.bmw
Dave Plowman (News)
external usenet poster
 
Posts: 1,533
Default Adaptive Headlights

In article >,
Richard Sexton > wrote:
> >> Daylight is blue.

> >
> >No it's not. By definition.


> Daylight is only not-blue at the equator.


The colour temperature of daylight varies by the time of day and weather
conditions as well as latitude.

--
*Shin: a device for finding furniture in the dark *

Dave Plowman London SW
To e-mail, change noise into sound.
  #24  
Old September 20th 06, 08:27 PM posted to alt.autos.bmw
Richard Sexton
external usenet poster
 
Posts: 285
Default Adaptive Headlights

In article >,
Dave Plowman (News) > wrote:
>In article >,
> Richard Sexton > wrote:
>I'm not objecting to you disagreeing - merely objecting to you calling my
>opinion naive. Which suggests I haven't given it any thought or know
>nothing about lighting.


The cost, complexity and lack of "instant on" make these non-starters in
automotice use for anything other than specialized purposes. IMO to suggest
all cars shpuld rely on HID sole; is naive. Nothing personal...

>But the 'simple and cheap' arguments are often put forward in favour of
>points and carbs. And those who do simply ignore efficiency.


I don't know anybody that prefers carbs to injection but I do know a few
folks that will not convert older cars to pointless systems. Maintenance
is minimal and they point out if/when they fail you can pretty much fix them
with a rock but if a pointless system fails, you're screwed. I'm neutral
on this and just keep my cars original.

>Again why? Many cars still have incandescent main beams. For signalling
>purposes if nothing else. No reason why they couldn't be incorporated into
>a main beam HID setup for just this reason.


I think it's the lack of an "instant on" abaility.

>The light output of any lamp can be increased or decreased. Saying you can
>already buy an 150 watt H7 incandescent but only a 35 watt HID is pretty
>meaningless in the scale of things. However, upping the wattage of an
>incandescent can often result in reflector or lens damage due to heat. And
>voltage drop in the wiring etc can also cause problems.


Understood. In halogen fixtured that have the bulb base and reflector than
can handle it you can ho pretty high. Not sure what's actually under debate
here.

>> >For things like tail lights etc you don't need omni directional
>> >radiation - indeed this just means you have to add some form of
>> >reflector.

>
>> No and no. You need to check lighting regulations and yo're guessing
>> (wrongly) about the reflector.

>
>The reflector behind a incandescent lamp in say an indicator or tail light
>- not a passive reflector needed for safety. Because ordinary incandescent
>bulbs have a near omnidirectional beam pattern, some form of crude
>reflector is needed to increase the efficiency. Not so with an LED type
>where the lens is built in.


LED"s shoot light out in one direction and lighting regulations require
signalling lamps be seen from more than one direction. It's an issue.

>> >For many applications around the car, filament or point source lamps
>> >are anything but ideal. Interior lighting for example would be better
>> >with large soft sources. As would most other lights apart from
>> >headlamps. We're simply used to filament lamps - that's all.

>
>> Well, I've tried LED's inside. Worthless. You go try it ane lemme know
>> what you think. Luxeons are nice ones to play with.

>
>LED technology has a long way to go - as with much else in lighting. But
>the sure thing is the tungsten filament bulb's days are numbered.


Perhaps, when LED's can do what incandescents too. But until then.

Hey I *hate* incandescents in the house and everythning is CFL here,
but having tried LEDS in the dask and dome lights - they just don't work
well at all.


--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
633CSi 250SE/C 300SD | http://aquaria.net http://killi.net
  #25  
Old September 20th 06, 08:30 PM posted to alt.autos.bmw
Richard Sexton
external usenet poster
 
Posts: 285
Default Adaptive Headlights

In article >,
Dave Plowman (News) > wrote:
>In article >,
> Richard Sexton > wrote:
>> >> Daylight is blue.
>> >
>> >No it's not. By definition.

>
>> Daylight is only not-blue at the equator.

>
>The colour temperature of daylight varies by the time of day and weather
>conditions as well as latitude.


Yeah, but all things being equal, on a clear day at noon light is
bluer towards the poles. 5000K is given at the equator by
several sources (GE, Horst & Kipper) and 6500-7500K is given
in "norther climes" whcih ranges from Boston to Denmark.

--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
633CSi 250SE/C 300SD | http://aquaria.net http://killi.net
  #26  
Old September 21st 06, 02:59 AM posted to alt.autos.bmw
Fred W[_1_]
external usenet poster
 
Posts: 210
Default Adaptive Headlights

Richard Sexton wrote:

>
> The cost, complexity and lack of "instant on" make these non-starters in
> automotice use for anything other than specialized purposes. IMO to suggest
> all cars shpuld rely on HID sole; is naive. Nothing personal...
>


As you say, that's your opinion. Of course it's wrong, but you are
entitled to your opinion.

"Instant on", as you put it, is a non issue. There are many, many cars
running with BiXenon setups that have no need for "instant on"
headlamps. They use a mechanical mask to create the low beam which
moves out of the way to provide main (high) beams.

Besides, instant on is a misnomer. Even halogens take a finite period
of time to begin to cast light. Yes, that is shorter than the time to
ignite an HID bulb, but who cares? When I engage the HID Xenon lights
on my car (not a BMW) they are lit in less than 1/2 a second. Why would
you need them to respond any faster than that?

The total quality of light is dramatically greater with HID and the
power demand from the alternator is less. HID lamps can be manufactured
that shed light of different wavelengths. 4300k is usually the absolute
greatest light quantity, and decreasing in output both wavelength
directions.

If your problem is that you don't think headlamps should have greater
than 5000k color temps then say so. It's not an issue with the method
of the light that you have, but rather the color.


--
-Fred W
  #27  
Old September 21st 06, 03:40 AM posted to alt.autos.bmw
Richard Sexton
external usenet poster
 
Posts: 285
Default Adaptive Headlights

In article >,
Fred W > wrote:
>Richard Sexton wrote:
>
>"Instant on", as you put it, is a non issue. There are many, many cars
>running with BiXenon setups that have no need for "instant on"
>headlamps. They use a mechanical mask to create the low beam which
>moves out of the way to provide main (high) beams.


I'm not sure what this has to do with "you turn the switch on and the
road it lit up".

>Besides, instant on is a misnomer. Even halogens take a finite period
>of time to begin to cast light. Yes, that is shorter than the time to


Uh yeah, a little.

>ignite an HID bulb, but who cares? When I engage the HID Xenon lights
>on my car (not a BMW) they are lit in less than 1/2 a second. Why would
>you need them to respond any faster than that?


Who'd have ever thought you need more than 640K ?

>The total quality of light is dramatically greater with HID and the
>power demand from the alternator is less. HID lamps can be manufactured
>that shed light of different wavelengths. 4300k is usually the absolute
>greatest light quantity, and decreasing in output both wavelength
>directions.


K is a measure of light color, not the amount of luminous flux; it's a
qualitative, not quantitice measurement. HIDs do draw less power, significantly
so. They do not put out more light than thr Cibie CSR's, which are halogen,
in my 633.

>If your problem is that you don't think headlamps should have greater
>than 5000k color temps then say so. It's not an issue with the method
>of the light that you have, but rather the color.


The color is the worst problem. But as long as I can get more light for 1/4 the
cost I see no point in HID lamps to say nothing of the fact it's easy to install
or adapt good halogens, but retroftting HIDs to any car is simply a fantasy.

It's a great technology to be sure, but its young and has a way to go.


--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
633CSi 250SE/C 300SD | http://aquaria.net http://killi.net
  #28  
Old September 21st 06, 12:15 PM posted to alt.autos.bmw
Fred W[_1_]
external usenet poster
 
Posts: 210
Default Adaptive Headlights

Richard Sexton wrote:
> In article >,
> Fred W > wrote:
>
>>Richard Sexton wrote:
>>
>>"Instant on", as you put it, is a non issue. There are many, many cars
>>running with BiXenon setups that have no need for "instant on"
>>headlamps. They use a mechanical mask to create the low beam which
>>moves out of the way to provide main (high) beams.

>
>
> I'm not sure what this has to do with "you turn the switch on and the
> road it lit up".


I thought your desire for "instant on" was in regard to switching on the
high beams. If all you a talking about is being able to instantly turn
on the low beams, well... I don't get it. Why do you need to do that?
I usually turn my low beams on long before actual dark and if they took
a minute or longer to turn on, it would be no big deal. But as I said,
it only takes a small fraction of a second, so who cares.

>
>
>>Besides, instant on is a misnomer. Even halogens take a finite period
>>of time to begin to cast light. Yes, that is shorter than the time to

>
>
> Uh yeah, a little.
>
>
>>ignite an HID bulb, but who cares? When I engage the HID Xenon lights
>>on my car (not a BMW) they are lit in less than 1/2 a second. Why would
>>you need them to respond any faster than that?

>
>
> Who'd have ever thought you need more than 640K ?
>


Huh? 640K what?

>
>>The total quality of light is dramatically greater with HID and the
>>power demand from the alternator is less. HID lamps can be manufactured
>>that shed light of different wavelengths. 4300k is usually the absolute
>>greatest light quantity, and decreasing in output both wavelength
>>directions.

>
>
> K is a measure of light color, not the amount of luminous flux; it's a
> qualitative, not quantitice measurement. HIDs do draw less power, significantly
> so. They do not put out more light than thr Cibie CSR's, which are halogen,
> in my 633.


I'm fully aware of that. What I'm saying is that the HID lamps that put
out light at 4300k *also* happen to be the ones that put out the most
candlepower for the same (35W) input.

There are maximum limits set by the DOT for candlepower over a range of
dimensions. If the Cibie's really do put out more (which I seriously
doubt) then they would be illegal here.

Your Cibie's don't fit in any modern cars. When was the last car made
that takes 5.25" round headlamps. They are also only available for
"wrong-hand drive" applications, as far as I can see. Comparing them to
factory Xenon HIDs (in the US anyway) is kind of moot.

>
>
>>If your problem is that you don't think headlamps should have greater
>>than 5000k color temps then say so. It's not an issue with the method
>>of the light that you have, but rather the color.

>
>
> The color is the worst problem. But as long as I can get more light for 1/4 the
> cost I see no point in HID lamps to say nothing of the fact it's easy to install
> or adapt good halogens, but retroftting HIDs to any car is simply a fantasy.


But my point was (is) the color doesn't *have* to be a problem. 4300k
HID is not blue in the least. In fact, 4300k happens to be in the
frequency range that the eye sees best. With lower or higher
frequencies a correction factor has to be applied to the measured light
quantity to determine the effective light power.

http://www.havis.com/havis_catalog/H...%20candella%22

And I have yet to see a car manufacturer offer up any car with halogen
lights that come anywhere close to the light output of the HIDs.

>
> It's a great technology to be sure, but its young and has a way to go.
>


Sure, they can be improved going forward, and I'm sure they will. But
they're already better than all the alternatives.


--
-Fred W
  #29  
Old September 21st 06, 03:53 PM posted to alt.autos.bmw
Jack[_1_]
external usenet poster
 
Posts: 75
Default Adaptive Headlights

http://www.intellexual.net/hid.html

This site appears to provide some credible info on HID lamps along with some
interesting 'prism tricks' employed by BMW and Audi that make their
headlights appear blue from the side even though they are actually white
(4100K). It seems clear from this site that the true high temperature 'blue
light' systems only have 'bling bling' value as they provide less light and
that the human eye is less able to see that light.

To the original poster with the night vision problem I would suggest that he
work on the other end of the problem and get some night vison glasses. I
have an emergent night vision problem and find these lenses help
significantly, especially in the rain. They also have the added benefit of
acting as BLUE BLOCKERS knocking down the intensity of the oncoming beams
from the affluent but ignorant purchasers of the blue light systems who for
some reason usually drive around with their high beams up.


"Richard Sexton" > wrote in message
...
> In article >,
> Dave Plowman (News) > wrote:
>>In article >,
>> Richard Sexton > wrote:
>>> >> Daylight is blue.
>>> >
>>> >No it's not. By definition.

>>
>>> Daylight is only not-blue at the equator.

>>
>>The colour temperature of daylight varies by the time of day and weather
>>conditions as well as latitude.

>
> Yeah, but all things being equal, on a clear day at noon light is
> bluer towards the poles. 5000K is given at the equator by
> several sources (GE, Horst & Kipper) and 6500-7500K is given
> in "norther climes" whcih ranges from Boston to Denmark.
>
> --
> Need Mercedes parts? http://parts.mbz.org
> Richard Sexton | Mercedes stuff: http://mbz.org
> 1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
> 633CSi 250SE/C 300SD | http://aquaria.net http://killi.net



  #30  
Old September 21st 06, 07:33 PM posted to alt.autos.bmw
Dave Plowman (News)
external usenet poster
 
Posts: 1,533
Default Adaptive Headlights

In article >,
Richard Sexton > wrote:
> >If your problem is that you don't think headlamps should have greater
> >than 5000k color temps then say so. It's not an issue with the method
> >of the light that you have, but rather the color.


> The color is the worst problem.


Have you ever driven a car with HID lighting? You very soon don't notice
the *slight* difference in colour temperature if you've got 4300k lamps.

> But as long as I can get more light for
> 1/4 the cost I see no point in HID lamps to say nothing of the fact it's
> easy to install or adapt good halogens, but retroftting HIDs to any car
> is simply a fantasy.


No it's not. I've driven a car with a conversion and it was fine -
although of course illegal in the UK. But then so are greater than 55 watt
halogens for dips.

> It's a great technology to be sure, but its young and has a way to go.


It's anything but young - the technology has been used in film etc
lighting for many years.

--
*El nino made me do it

Dave Plowman London SW
To e-mail, change noise into sound.
 




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