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A head light comparison
I got this on the MB list that I am part of. Really interesting stuff.
Maybe it will help some of you.
Being a "headlight enthusiast" :-) , the latest catalogs from PIAA have
interesting new offering which I subsequently examined. Their new "Platinum
Super White" series of bulbs claims two advantages:
(1) the light has a color temperature closer to real Xenon (i.e., real High
Intensity Discharge or Litronic) systems than other incandescents, for a
whiter output; specifically, PIAA claims a color temperature of 3,800ƒK,
compared to 4,300ƒK for a HID, and only 3,200ƒ and 2,600ƒ for halogen and
halogen incandescent bulbs (all of these values are claims from PIAA's
catalog's, of which there are two: 1999 Consumer Catalog, and 1998
Supplemental Product Catalog).
And in addition,
(2) "XTRA" technology that allows the bulbs to burn brighter using less
amperate, so that their light is equivalent to conventional bulbs of about
Such claims piqued my interest, and I decided to examine them closely.
PIAA offers these bulbs in the following versions:
H4 60/55W (claimed equivalent to 110/100W halogens)
H4 80/80W (claimed equivalent to 135/115W halogens)
H3 55W (claimed equivalent to 85W halogens)
H3 85W (claimed equivalent to 135W halogens)
9004 65/45w (claimed equivelent to 110/85W)
9005 60W (claimed equivalent to 110W)
and 9006 51W (claimed equivalent to 100W)
I ordered an H4 60/55W bulb (#15060) for my trials, as it was the cheapest
(at "only" $38) and I wasn't ready for such a commitment to equip both of my
Euroheadlight-fitted cars until I knew what I was getting.
I had three particular interests:
(1) are they whiter? I am a fan of the new HID Xenons (though my '90 W-124
and '88 W-201 can't be retrofitted with the "real thing"), in part because I
agree that the whiter (closer to sunlight) color makes seeing certain
objects (dangers) at night easier. However, I don't like the excessively
color of pseudo-HID Xenon fakes that are being sold.
(2) are they brighter? PIAA's claims for the XTRA technology seems like a
"free lunch", so to speak, in that I could get more illumination without
consuming more wattage (and loads on alternators, batteries and
(3) are they more efficient? I.e., really not using more wattage? Again,
because of the same considerations as in (2), above.
My W-124 and W-201, both with Euroheadlights, were equipped with PIAA's
"regular" 90/75W H4's (#14090). I used them (and a couple of other halogens
that I had on hand) to compare to the new Platinum SuperWhites in 60/55W.
My first test was of the truthfulness of their wattage claims. I made
measurements off of an out-of-car automobile battery (while receiving
continual recharging from a line-powered battery charger). Voltage and
amperage measurements were made with two Fluke digital VOM's (Multimeters)
measure both parameters simultaneously. In the following table, "Amps" is
flow through the bulb (of course), "@ volts" is the voltage measured across
the bulb (different wattages affect the battery's ability to provide
and "Watts" is what I calculated as the product of Amps and volts.
Bulb Amps (@ volts) Watts
PIAA 60/55 H4 55W: 4.56 14.1 64.3
60W: 4.95 13.9 68.8
PIAA 90/75 H4 75W: 5.54 14.1 78.1
90W: 6.58 13.9 91.4
Osram 100W H1 7.18 14.0 100.7
60/55W H4 55W: 5.02 14.0 70.
60W: 5.20 14.0 72.9
What we can see from the above table is that PIAA's new SuperWhite 60/55W
are a little underrated in wattage: they seem to draw about 73/70 Watts.
claims the XTRA-technology bulb's label's wattage provides the output of a
110/100W ordinary bulb, but their bulb's actual wattage (as I measured it)
perhaps explains at least some higher light output (if any). Note that I
measured higher wattages for PIAA's normal 60/55W H4, while I measured
"appropriate" wattages for other bulbs -- perhaps PIAA routinely offers
wattage filaments in their 60/55W H4's.
The next thing I tested was whether they are brighter. I used a Sekonic
Photographic Digital Light Meter using their "incident light" mode, and
measured the three different H4's using the "EV" scale (which measures to
nearest 1/10 EV). BTW, "EV" is a scale, in comparison to "lux", such that
each single digit increase in EV doubles the Lux value (e.g., EV 1, 2 and 3
can equal 5, 10 and 20 Lux at a certain setting). My technique (distance to
the bulb, orientation of the bulb, ISO scale on the meter, etc.) was
"controlled" as well as I could in my garage. I don't expect perfect
repetition from others of you, but I'll stand by my comparisons among the
bulbs (I have a Ph.D. in Biology, so I have an appreciation of the
method). The bulbs, in this test, were bare; the results:
H4 Bulb type High beam Low beam
PIAA Reg. 60/55W 6.7 6.5
PIAA Reg. 90/75W 7.6 7.0
60/55W 6.7 6.5
Isn't this interesting! Although PIAA claims higher light output (the
equivalent of a 110/100W H4), I measured, in this test, for their SuperWhite
bulb exactly the same light output as an ordinary H4 of the same labelled
wattage; moreover, the previous tests on wattage revealed that the regular
bulb was using less wattage than the SuperWhite (mid-60's vs. low-70's
wattage)! It would seem that the regular H4's were more "efficient",
the claims of "XTRA" technology.
But, let's consider some other factors. The PIAA SuperWhite bulb has a
noticeable blueish coating, which should reduce some output. Also, the
photographic light meter has some spectral bias, being more sensitive to the
red end (which is why foliage, which emits a lot of long-wavelenth IR, looks
darker in photos: the meter thought it was brighter than it really is to
emulsion sensitivity). Thus, the redder (or "oranger") regular halogen
seem brighter, to the meter, than the bluer SuperWhite bulb's emissions.
frankly, I cannot believe that this explains more than a very slight error
In the last part, I'll measure brightness in a headlight (instead of the
aforementioned bare-bulb condition), and comment on the color.
Summarizing from the previous mesages, I found that the PIAA SuperWhite
H4 used more wattage than claimed (73/70W, measured) and yet (measured bare-
bulb) did not produced as much light as a regular 90/75, let alone the
equivalence to a 110/100W H4.
The next step was to install the new PIAA SuperWhite 60/55W H4 in my car
(fitted with Euroheadlights) on one side, to compare against an already
installed PIAA regular 90/75W H4. I was interested in two things: an
alternative measure of brightness (i.e., in a lamp housing, instead of the
"bare bulb" measure); and my impressions of the bulb's "color".
PIAA claims that these SuperWhite bulbs, with XTRA technology, is so much
more efficient that the 60/55W that I have is equivalent to a 110/100W
H4. I installed the new SuperWhite on one side, and left the regular (and I
should add, two year-old) 90/75W H4 on the other. Then I turned on the
headlights and again used my photographic incident light meter (described in
part 2) to measure the brightness of each headlight a specific distance
Measured at the brightness center (as seen against a wall) on LOW beam,
regular 90/75W measured 9.0 EV. In comparison, the 60/55W SuperWhite (with
claimed output equivalent to 110/100W and an actual wattage measured by me
73/70W) registered 8.5 EV. On HIGH Beam, their differences were consistent:
the higher wattage regular H4 measured 9.6 EV, while the lower wattage (but
claimed superior) SuperWhite H4 measured 9.1 EV.
Now that we can put aside claims of greater efficiency (light per Watt)
brightness, I addressed color. No, I don't have a photographic color meter
(anyone want to lend me one?), but I'll tell you that I did notice, and
approve of, the color of the new SuperWhites. As I wrote earlier (part 1, I
think), I like true Xenons' color, but don't like the excessive blue of the
many faux-Xenon incandescent halogen fakes that I've seen on the road. This
PIAA is also a "faux-Xenon", of course, but their color doesn't look blue by
itself, but only in comparison to the regular halogen in the other
By itself, it just looks "whiter", and I like it very much. It makes the
Euroheadlights of my MB look "colder", and very suitable -- this is a
subjective evaluation, you understand :-).
I (as I explained) only bought one bulb, so I'm not installing it in
of my Euroheadlight-equipped cars (I don't want two different colored lights
in my car). Based on the better color, however, I am going to order two
of higher-wattage SuperWhites (80/80W) to replace the 90/75W bulbs in the
now. Then I'll see how they perform on the road (viz., visability of
at night) and pass my observations on to you folks. Stay tuned.
This gentleman is the author: KenAC@aol.com