Was: Carello vs Hella - now halogen lighting - long

[Bruce Blair <bblair@domain.elided>]

In a 'previous life' (1974 thru 1981),  I was an importer/wholesale 
distributor of automotive lighting products, Cibie' at first, then Hella 
and some other lower priced lines.  Here is some background on halogen 
automotive lighting.

The top four producers of automotive OEM headlamps in those days were 
Cibie, Hella, Marchal and Carello,   and Lucas to some extent.
They each had there market share of manufacturers for which they made the 
multitude of standard round headlamps, as well as the sometimes oddly 
shaped but stylish custom headlamps particular to certain models.

All of these headlamps used the same family of bulbs,  and the light 
patterns generated were also regulated.  The legislative approvals were 
signified by the E-Code molded in to the lens.  This was within a circle 
with a large letter 'E' followed by a number unique to the manufacturer 
,  and then outside the circle was the number that was unique to that 
particular lens/reflector assembly.

The low end OEM bulbs were the tungsten filament 'Type A' bulb,  a two 
filament bulb with a large round globe and a round metal mounting 
base.  These were 45w maximum I believe.

The 'halogen' ,  or more accurately 'quartz-halogen' bulbs , were a small 
quartz glass bulb filled with an inert halogen gas, and one or two tungsten 
filaments.  The filaments were able to produce the remarkable amount of 
light for their current consumption by using the 'halogen cycle' to prevent 
burn-out.  By putting the same current through a smaller filament  they 
burned brighter, and the tungsten particles that would normally fly off and 
be deposited on the glass globe (why the vacuum globed tungsten lights got 
dimmer with age) were not able to because of the chemical reaction with the 
halogen gas,  and would end up re-deposited back on the filament. The 
quartz glass was used to withstand the extreme heat of these brighter 
filaments.  The bulbs came packaged with instructions or pictograms warning 
users not to touch the globe.  Oil from your fingers would contaminate the 
glass and cause a hot spot and the glass globe could crack.

The thing that separated these lights from the US SAE mandated sealed 
beams, which by the way dated back to the 1930s, was that the bulb was 
replaceable without throwing away the entire lens/reflector assembly,  and 
the beam patterns produced were much more accurate and controlled.    They 
also had the benefit of still producing light even if the lens were broken 
out.  GE and Westinghouse at the time had an armlock on the US automotive 
lighting market.  By US standards,  replaceable bulb type headlamps were 
not legal for road use.

The sealed beams were mass produced and the light pattern produced by them 
was somewhat less than accurate - mostly a blob of light produced from a 
pop-bottle type molded lens of poor optical quality glass.

The high end E-Code headlamps mentioned above used expensive high lead 
content glass, with excellent optical qualities, and with sharply defined 
fluting to control the light beam accurately.     The light pattern is 
totally dependant on the lens fluting for its shape.  The same parabolic 
reflector with no lens will produce almost a laser-like 'pencil' beam, and 
then by adding flutes to the glass lens this can be spread and controlled 
to meet the various light patterns needed.   The original E-Code low beam 
headlamp has a flat top beam pattern from the left side to the center, then 
rising up at an angle toward the ditch side of the road. This was good for 
many years,  but the advent of multilane highways caused them to revise the 
pattern to avoid blinding via rear-view mirror the drivers of cars being 
passed in the same traveling in the same direction.  This was the Cibie 
Z-Beam, and was later adopted by other manufacturers.

High beam headlamps from the four headlamp setup were usually a fairly 
tight, round, long distance pattern,  with the area closer to the car 
covered by the high beam filament of the low beam lamp.

Auxiliary fog lamps were a wide flat top beam,  and were designed to be 
mounted low on the car.  This allows the driver to look through unlighted 
water droplets to a lighted road beneath, eliminating most of the 
reflection and refraction from the fog,  since fog rarely goes completely 
to the ground.  Check it out sometime-  it's clear down there at ground level.

To debunk an popular myth -  color does not make a fog light.   If it's 
amber, it doesn't make it a fog light.  ONLY the light pattern generated 
makes it a fog light.   For many years, France used amber lighting 
exclusively  -  for all headlamps, driving lamps,  and fog lamps.  Amber 
lighting DOES reduce eyestrain,  and increases contrast,   but at the 
expense of slightly reduced output.


So -  to get back to the original question -     with the same halogen H4 
bulb, usually 60/55 watt,  for low beam,  or the H-1 55w standard high beam 
bulb, the choice of headlamp is a matter of personal preference,  mostly 
relating to the physical appearance of the lens,  not it's output.  They 
all should meet the same beam pattern requirements.  Some are made of 
better quality glass,  thicker glass, more sharply formed fluting, have 
better coatings on the reflector to last longer,  the rubber boot sealing 
the bulb area may be better designed, and the material for the reflector 
may be thicker or more accurately formed for better light patterns.   It's 
a case of 'you get what you pay for', in the end.   The very inexpensive 
versions may not meet ANY recognized standard.  A flat lens of poor quality 
may be more prone to cracking from the temperature extremes it is subjected 
to -  a very hot bulb close behind it and the ambient conditions (cold, 
rain, snow) on the front of the lens.  Most halogen lamps have the lens at 
a good distance from the bulb, helped by the convex shape.


As an aside,  in the late 70's,  we lobbied extensively in the Pacific 
Northwest,  even giving demonstrations to Joan Claybrook,  then of the 
NHTSA, and many other state legislators, in our facility, with the end 
result that Oregon and Washington were the first two states to legalize 
"E-Code" headlamps,  by adopting the CSA (Canadian Standards Organization) 
certification which allowed them, as an alternative to the SAE 
standard.  This may be why some headlamps are still marketed with the 'Off 
Road Use Only' tag -  they may not meet CSA or SAE standards or some states 
still require SAE standard headlamps.


Bruce Blair
Seattle, WA



At 06:05 PM 10/17/01 -0700, Alan Lambert wrote:
>I can get Carello high beams (H-1) for the GTV-6 in England for about
>$60.00 (plus shipping) apiece. Hella ("off road only") H-1s for about
>$54.00 here. (no shipping)
>
>What's the group's opinion about a comparison between Carello and
>Hella? If Carello's give more light, are they worth the time and cost
>difference?
>
>thanks
>
>=====
>Best Regards,
>
>Alan Lambert

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