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Thanks henry k, the xenon is not mentioned on the packaging.
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The press release is misleading, in that it doesn't say the Stop Tail lights are Xenon, but it can be implied.
The Xenon reference is in the next paragraph, where the description is about the Headlights.
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So, are we back to snake oil?
Edited by Old Navy on 29/07/2008 at 15:33
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This is Halfords - they wouldn't make unwarranted claims.... Would they?
Obviously; these bulbs must contain sophisticated Halfords-developed electronics that emit a wide-band EMF field behind the car, which permeates the nervous system of following drivers and strips away any age-related deterioration in neurons and synapses, restoring near-pubescent levels of reaction time - the claimed 50% improvement - but now coupled with experience-honed judgement.
So; a sort of brake-reaction-time Viagra - or, as Sir Robert Mark would say, "a major contibution to road safety."
Edited by Screwloose on 29/07/2008 at 16:18
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>>This is Halfords - they wouldn't make unwarranted claims.... Would they?
They did when they claimed a certain oil filter was suitable for a certain engine (no non-return valve), and it obviously wasn't.
I think that cost them a few bob in replacement engines, although to be fair they weren't the only ones with inaccurate application charts.
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I wonder if there is any evidence to back that up bathtub?
Not many filters around without a non return valve in. maybe it was a different problem?
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Old Navy, you seem determined to strongly suggest or imply that the performance claims made by Halfords are untrue, but you put forward nothing on which to base your criticism.
So, please clear up one confusion for us:
Are you claiming that a lamp that reaches full brilliance in a shorter time (than a conventional lamp) does NOT give more time for a following driver to react before a collision occurs?
Or are you claiming that the QR lamp is NOT "designed to illuminate more quickly than standard rear bulbs".
Or are you claiming that, whatever the design, the lamps WILL NOT "illuminate more quickly than standard rear bulbs".
Or are you claiming something else?
Really, I can see no useful purpose in your continued attempts to cast doubt on the integrity of the claims by Halfords; unless, of course, trolling is your chosen pastime?
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Thank you -Please evidence what you're saying or they're chopped under naming and shaming policy.
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having read the halfords press release i think an important fact is being missed and that is that they claim a reduction in reaction time in POOR conditions, by which im presuming that the light from the bulbs is more noticable then standard bulbs in poor conditions.
I dont see any blanket statements saying the bulbs work faster, better etc in all conditions only in poor conditions, meaning these bulbs manage somehow to filter though weather elements that would otherwise hamper the driver behind.
seems these days we are all guilty of needing to find a lie even when there isnt one
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A very profound thought.
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I can understand that LED lights 'light up' far quicker than incandescents. i.e. to all intents and purposes LED's are on or off while incandescents take some time to come to full brightness. In practice the time difference is so small that it is of no account. LED's however pactically eliminate the 'failed bulb' situation. That has to be a plus. The only way that I can see hat makes incandescents light up faster is a lower initial resistance with a similar final resistance to keep within the 21W limit. then again I may be talking through my hat
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I used to think that about LEDs - a couple of years ago the council around where we stay in Wales changed all their traffic lights to LED types. The ones in Caernarfon by Tesco have become rather "patchy" as have ones in Llanrug village by the old Peugeot garage.....
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agreed. and i noticed them as well. 'Dwi'n ei gweld pob dydd. I'd still rather have a few elaments down than a total failiure any day
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oops. typo fairy strikes again. well, I'm typing a foreign language after all
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What about this "Tino" thing then - is Mrs P (a non-native learner) having me on ?
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I'm confuddled
E-mail sent - PU
Edited by Pugugly on 29/07/2008 at 21:50
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>>I can understand that LED lights 'light up' far quicker than incandescents
>>
Some info on LEDs. I have no "connection" with this outfit and am just quoting their site info.
www.superbrightleds.com/tail-brake-turn.html
Brightness of LED Car Bulbs
LED bulbs are generally not as bright as standard incandescent bulbs, they have many advantages over filament bulbs (longer life, faster on/off times, lower power consumption, more vivid colors) but brightness is not one of them.
They are generally not as bright but some of them with large numbers of LEDs, will appear brighter than filament bulbs.
How do your LED bulbs achieve dual intensity?
All of our Tail/Brake bulbs achieve dual intensity modes by turning all of the LEDs on dim or all of the LEDs on bright, all of the LEDs are always lit when either mode is active.
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"Halfords QR Stop, Tail and Flasher Bulbs have been designed to illuminate more quickly than standard rear bulbs for safer motoring. Priced at £3.99 per 12v 21w bulb, the innovative QR bulbs reduce the reaction time of other road users behind you."
There's not the slightest explanation in that press release of the revolutionary mechanism by which these very old-tech bulbs are allegedly "faster lighting" or "high intensity." They are still limited to 21/5 watt.
Incandescent bulbs have been around a very long time; the technology is over-mature and they don't make any claims in that carefully-worded piece that can't be weaselled-out of by a good lawyer....
All I see is slick marketing of very ordinary 380 bulbs - which I can buy for 23p - for a staggering £3.99 a pop!
Rip-off or what?
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The rear windscreen of my Bora has an red LED strip - it's pretty bright and lights up very rapidly with just a touch of the brake pedal.
Easy way to check the speed of reaction is at night via the rear view mirror when stationary.
Edited by Stuartli on 29/07/2008 at 23:03
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Easy way to check the speed of reaction is at night via the rear view mirror when stationary.
preferably in someone else's car :-)
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Thinking about it; I reckon I've sussed it - and it is quite a con. [Or a fraud?]
These are 12 volt bulbs.
Although that may appear initially unsurprising, it's actually unusual. Although car bulbs are marked "12v," they're actually 14 volt optimized - as that's the charging voltage of 99% of cars and their "normal" working voltage.
Making bulbs optimized for 12 volts would mean that they'd reach full brilliance slightly quicker and burn brighter than the regular 14 volt ones - but it would severely compromise their lifespan in the process.
Making 12v-optimized, but otherwise standard, bulbs would add nothing to the production cost - only 2 or 3p anyway - but it would allow the marketing guff that "justifies" the eye-watering price - and ensures repeat purchases on a very regular basis.....
One for HJ to look into....?
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Sounds reasonable Screwloose, given that the design of filament lamps has changed very little in the last 100years then it's unlikely someone could come up with something radical now!
>>seems these days we are all guilty of needing to find a lie even when there isnt one
I think that is a (reasonable?) reaction to ever more cynical / OTT marketing campaigns and general 'spin':-/
Plus the press release uses that well worn phrase " up to 50%" which of course includes 25%, 0% and -50% ...
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Thinking about it; I reckon I've sussed it >>
Thanks Screwloose, as my electrical knowledge streches to "cant see it, smell it, and it bites when you touch it" your assesment seems logical.
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Screwloose,
I would not normally question your analytical approach to automotive problems, but in this case can I add a couple of possible suggestions. The time to full (or least significant early)brilliance (I would guess) is a function of
1. the thermal capacity of the filament,
2. the thermal capacity and conductivity of the support mechanism,
3. the profile of temperature coefficient (of resistivity) of the filament
4. the thermal conductivity the inert gas in the envelope
for any ordinary incandescent bulb.
For 'halogen' bulbs there is the complication of a reversible chemical reaction taking place.
It maybe possible to design a bulb such that the inrush current is greater than normal, resulting in quicker warm up, but by playing with 3 to only consume a normal current at the nominal operating voltage and temperature.
All of which could be optimised for different applications. Whether it is possible to play with these features sufficiently to give a decreased time without compromising the bulblife is the bit of unique magic that maybe the halfords manufacturer has discovered.
pmh
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pmh
Yes to all of that; but essentially, in such a crudely-made component, it's only 3 that is a variable tuned to a particular operating voltage. [There are, very odd-looking, halogen 21 watt bulbs; but no claim of such in this case.]
Given the claim of "high-intensity" allied to the faster illumination: can you think of any breakthrough that could account for both - other than a thinner filament?
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screwloose
Rereading my post I can see that it could be ambiguous - when I referred to '3' I meant point3 ie 'the profile of temperature coefficient (of resistivity) of the filament'. - meaning a non linear response.
Just as an example, suppose you could have 2 parallel 'filaments'
one thin one which would lite up quickly, but once warm increased in resistance to reduce the current to very significantly to provide a long life
and one coventional filament that lit up slowly to provide the normal ligt output.
You could then possibly meet the criteria that they have suggested.
This is purely hypothetical of course and also disregards the possibility of some active electronics controlling the current flow.
(You can see I am bored, SWMBO has just broken her ankle and results in me being partially housebound. Not a good way to spend a 6 week holiday in the Sun!)
pmh
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Your meaning was very understandable - I meant point 3 too.
I learned years ago that the resistance of a cold filament bears no relationship to the working current consumption of a bulb; but I see no claims of revolutionary, or paired-filament, technology for these particular bulbs.
Would you agree that a filament optimized to a slightly lower than normal voltage would provide the claimed "benefits?"
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Would you agree that a filament optimized to a slightly lower than normal voltage would provide the claimed "benefits?"
Yes - but at what cost in terms of bulb life?
I cannot find the original 'authorative 'source, but the following gives a clue.
"According to one authoritative source, life expectancy is decreased to 50% by 5% over voltage (eg: 0.6V on 12V) and by about 75% by 10% over voltage". ( pmh comment -This may not be so true for a halogen filled lamp).
I doubt whether this degradation would be commercially acceptable.
I wonder what would happen to a single filament made from 2 dissimilar metals, providing thermal expansion problems could be overcome. The brain is starting to hurt!
IIRC there is contributor on this site who was in the 'lamp' development industry. He could possibly add some authorative info. I think that he has previously posted about the correct terminology for lamps bulbs etc.....
pmh
Edited by pmh on 30/07/2008 at 18:12
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What if they make the filament from something different from the usual Tungsten? A ceramic maybe? Carbon nanotube?
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the human eye can see a lit candle from about 12 miles away, how close do we need to see a brake light from?
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