Are your headlight lenses getting cloudy?

A 1998 Chevy Metro and a 1993 Dodge Neon both have the opaque headlights...
both made in Japan, as if that really has an impact on the usage of poor
quality plastic lenses.

My 1992 Chrysler and 2000 Dodge with plastic lenses showed no problems.

 

Wattage x efficiency = light output.

And as Einstein proved: "Time = money" (Gary Larson - Far Side™)

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Honest advertising can work. I agree with you regarding the type you are
talking about, however there is a more simple form of advertising that
just let's people know a certain thing or store or special deal exists.
It isn't there to create an image, but to show that store Y carries X for
less than store Z or to show that product A out performs product B with
straight forward testing. The advertising world would still exist just
fine doing this sort of work.

The companies that make and sell things could care less about us. I've
found more and more companies are catering to what I call the "moron
majority". Products becoming cost reduced and cheaped etc because the
majority doesn't care or even notice. I believe that this is key to why
cars offered in this country are the way they are compared to those
offered overseas.

Also, there is a mentality in US corporations that everything is
marketing, not product. The product itself simply doesn't matter to
people who are in charge. They only care about the marketing spin and
selling it. Convincing people they need the latest crap.

Water. I get strange looks when a place doesn't carry what I drink and I
then opt for water.

 

But don't they pretty much corrolate?
I have 80/100 watt h4 bulbs in 7" housings
on my scout, and they are much brighter than
the previous "normal" h4 bulbs I had in the
housing.

I had thought that previously you had advised the
xtravisions as the best U.S. market sylvania bulbs.

Bernard

 

Are you sure? perhaps he saw a Volvo, and thought it was a Mercedes.

 

You still dont point out where I find those stats and how they are
compiled...
dont point me at some cause-promoting website homepage and tell me to look
there... even though I agree with his global-warming editorial, i have too
much to do to just cruise around looking for stats.

I already posted my opinion and a link to back it.

IOW, put up or shut up....For an engineer you really do drink the kool-aid!

 

Usually, but only within a given technolgy. For example, HIR's produce
more light (49% for high beam, 88% more for low beam) with the exact
same wattage as OEM halogen bulbs (9005 & 9006). Any difference is
quantified as "efficiency".

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Even if he did see a Volvo, Volvo has only used plastic lenses on one model,
and that has not even been two years. Volvo has specifically fought Ford
about using Plastic headlights. They do not like the reliability of the
lenses as they scratch easily, and also the lighting performance is
diminished. When I worked there we were always telling the engineers
customers wanted HID headlamps, and clear plastic lenses as they looked
better. And the Swedes spit up and down about what a stupid idea it was. I
forget the term but Stern probably knows it ( but the Engineers said that
glass lenses with the patterns formed in them provided a better visibilty
beam then using clear lenses and HIDS or reflectors for clear lenses. The
engineers did not like the added weight of the headlamps, but said they were
better for Volvo's because of the safety factor. Volvo also had an extensive
study on Hid's and showed us the video's and pictures of hids in the snow,
and on dark forest roads. And by far the conventional bulb was far superior
to HIDS. the video and pictures showed how hids cut off the lighting on
hills and corners far more then with conventional lighting. I think I still
have the binder on ligting from Volvo around somewere.

Given that, HIDS are optional with Volvo's today!

 

Not even then. Plain ol' halogen headlamp bulbs:

9006, 12.8v 55w: 1000 lumens
H2, 12.8v 55w: 1980 lumens

There are lots of factors that go into luminous efficacy (lumens out per
watt in).

 

Well...no. The Metro's lamps were made in Japan, but there's no such thing
as a 1993 Dodge Neon (the Neon was introduced in 1995), and the Neon's
headlamps are US-made.

 

Almost. What you call "efficiency" is actually _efficacy_, in lumens per
watt. So, wattage times lumens/watt equals lumens, 'cause watts drop out.

 

No.

H4 low beam, 12v 55w, 890 lumens
H2, 12v 55w, 1890 lumens
H3, 12v 55w, 1350 lumens
H1, 12v 55w, 1500 lumens

etc.

Well, sure, but that's a different question.

Bulbs, yes I did, though that's no longer the case. Sealed beams, no.

 

Don't be lazy, mouse around the site. It takes about two clicks to find
the stats and very detailed info on how they were compiled. Want more? Buy
the book.

And you have a *very* big job ahead of you if you're planning on
questioning Leonard Evans' credentials.

 

I'm under the impression that "efficiency" (in any engineering context)
is always some desired output for a given input, and, for a given
process, device, or technology, it only remains for the exploiters of
that technology to precisely determine what the desired output and the
input (typically cost and/or energy) is, and thus to define the formula
for efficiency in the context of that process, device, or technology. I
think any engineer would accept the lumens out over wattage in as the
efficiency. The fact that the lighting industry has chosen the use the
word "efficacy" instead is fine, and anyone who works in the industry
would simply be being obstinate to try to insist that it only be called
only one or the other. Technically either one is correct.

Hmmm - heres what my Websters says:
Efficacy: Power to produce effects or intended results; effectiveness.
Efficiency: (1) Ability to produce the desired effect with minimum of
effort, expense or waste; quality or fact of being efficient. (2) The
ratio of effective work to the energy expended in producing it, as of a
machine; output divided by input.

That last sentence is why I say they can be used interchangeably: Output
(lumens) divided by input (watts). Lumens represents light energy.
Heat is the loss between input and output for lighting as well as in a
machine (friction).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Not really. Efficiency, in the context of light bulbs, is related to
thermo-
dynamic efficiency. A 100-watt tungsten-filament light bulb uses 100%
of the input energy to produce 100 watts of output radiation, as does a
100 watt fluorescent, as does a 100 watt (set of) LEDs. In that respect,
they are all 100% efficient.

However, only about 40% of the tungsten filament's output is in the
human eye's light band: the rest is infra-red (heat) output. Much less
fluorescent and LED output is infra-red (since they use quantum effects
to emit photons from limited electron-state transitions, as opposed to
emission from many states.)

Efficacy is a better, and more precise, term.

FloydR

 

Sure, but as in many other fields, the generic meanings of the terms are
not necessarily the ones that hold sway.

Efficiency and efficacy are not the same thing in the lighting field. Go
over to sci.engr.lighting and try your Webster's citation on that group --
see how far you get with it!

Efficacy: Lumens per watt. Amount of light out over amount of electricity
in.

Efficiency: More ethereal, refers to amount of *usable* light out over
amount of electricity in.

 

H'm. Offhand, Volvos with plastic lenses:

'86-'93 240
'89-'94 740 and 940 w/flat-nose
Recently, possibly XC90 or maybe late S60.

The HID demand makes sense, because most people swallow the marketeers'
hype and believe that HID headlamps are necessarily better, which they are
not. Good headlamps are better than bad headlamps, and there are good and
bad HID headlamps and good and bad halogen ones.

The "customers want clear plastic lenses" part doesn't make sense.
"Customers want clear lenses" would make more sense.

That's true. Lens optics combined with complex-surface reflectors provide
the best overall beam focus and formation. But the stylists' insistence on
clear lenses carries a lot of weight. There are some good complex-surface
clear-lens lamps, but in general their focus and formation aren't as good
because the beam optimization provided by the lens optics is lost.
Marketeers have never tended to let facts like that interfere with their
mountains of BS, though, so we now have the common and utterly incorrect
belief that clear-lens headlamps are more efficient, let more light out,
etc. etc.

Yes. Not very good ones, though!

DS

 

David-

Please shoot me an e-mail. info "at" danielsternlighting "dot" com .

Thanks,

DS

 

Not true. If what you're saying is true, then the word "efficiency" has
no meaning for mechanical machines either - because, by your reasoning,
you would add the losses there (called friction) into the output as
well. And you know darn well you don't. The output in the efficiency
equation in either case is everything excpet the heat (friction = heat,
thermal radiation of a light bulb is heat).

When talking about efficiency of any machine, you don't count the wasted
heat as part of the desired output (unless the desired output is heat,
like in a water heater). You don't count the waste heat when talking
about alternator efficiency or in combusting gasoline in an engine
'cause if you added it al up, you would have 100% efficiency as you
said. That would be meaningless and of course is not done.

Waste heat in a lightbulb is not useful energy - it is not counted as
part of the output in efficacy, or efficiency if you like, when talking
about light bulbs.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

OK - so 'efficiency' would actually be a more meaningful term - since
what people are really interested in is "useable" light for wattage put
in (and for good or bad, fits more with what Websters says for
'efficacy' - wouldn't be the first time that technical definitions don't
go along with the common or dictionary usage).

But if 'efficacy' is the term they use in the industry, then that is
what they use, even though people are more interested in *useable* light
per watt and therefore it seems like an inferior term for lights used
for the purpose of illumination that humans can see and use. I guess
measuring useable light would require filtering out wavelengths outside
of a certain defined *visible* band. Perhaps that band is not so easily
defined, hence your saying that 'efficiency' is a more *ethereal* term.

Hmmm - let's see. Ethereal: Of or like the ether, or upper regions of
space; hence, very light; airy; delicate: as, the ethereal grace of her
dancing. Heavenly; celestial; not earthly. In chemistry, of , like, or
containing ether. Just messin' with you now.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')