Halogen bulbs - color temperature vs. heat

_HighVoltage_

Captain Volvo
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I should know this, and I even googled it but came up empty.

Let's say we have two 55w halogen bulbs, one is clear the other has a blue tint. There is visible difference in color temperature (3000k vs 5000k), but what about heat produced? I know how overall power is produced (amps x volts) and that is obviously the same with both bulbs, but I'm also aware that only ~3% of these 55w are in light, the rest is in heat.

Or to be more specific - is there a realistic chance a 55w halogen bulb can melt the plastic connector on the harness just because of difference in color temperature?
 
The filament in the bulb with higher color temp (5000K) will get hotter for the same input power, because the filament is thinner and coiled tighter. Ironically, the light is usually referred to as cool-white, while the physical effect is exactly the opposite :lol: Hotter filament is more efficient, because the larger portion of the emittance is in the visible range, so it's brighter. It will also last less long, because of the higher temperatures.

It will not cause any more stress on the electrical system as long as both are 55W. The output power in terms of radiant heat will also be the same, just the spectral distribution is different. The heat that is conducted into the socket will be a bit higher, but I doubt the change is dramatic.

Alternatively, the glass itself may have a blue tint, which is complete bullshit and you shouldn't buy that.
 
The filament in the bulb with higher color temp (5000K) will get hotter for the same input power, because the filament is thinner and coiled tighter. Ironically, the light is usually referred to as cool-white, while the physical effect is exactly the opposite :lol: Hotter filament is more efficient, because the larger portion of the emittance is in the visible range, so it's brighter. It will also last less long, because of the higher temperatures.

It will not cause any more stress on the electrical system as long as both are 55W. The output power in terms of radiant heat will also be the same, just the spectral distribution is different. The heat that is conducted into the socket will be a bit higher, but I doubt the change is dramatic.

Alternatively, the glass itself may have a blue tint, which is complete bullshit and you shouldn't buy that.

Thanks for the explanation.

Yeah, I've heard that about the blue tint bulbs, but I compared them last night and the marketing is correct - in terms of light output they are on par with a generic bulb (at least visibly, you can't tell the difference). But the difference in color temperate is dramatic:

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Those are Phillips Diamond Vision bulbs, so at least they are from a reputable brand.
 
The new reflectors have the clearest cutoff I've seen on a car with reflector housings. And I did order ceramic connectors just in case. If I need more intense light I can at some point upgrade to the Osram Rallye bulbs (65W). These are glass lenses so nothing will melt or deteriorate up front.
 
Yeah, I've heard that about the blue tint bulbs, but I compared them last night and the marketing is correct - in terms of light output they are on par with a generic bulb (at least visibly, you can't tell the difference). But the difference in color temperate is dramatic:

Well sure, if what you wanted is just whiter light, that's a solution. Blue tint reduces luminance by cutting red light, and they compensate for that by running filament hotter. So you're sacrificing bulb lifetime (and price) for style, not for the amount of light :p On the other hand, Osram Nightbreaker or Philips X-Treme Vision use clear bulb with high-temp filament (still 55W), so they actually do output more light, although they wont look as cold-white.
 
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Technically, I already had a set of H7 Diamond Visions (blue tint) with my previous headlights. I ran them for over a year and they didn't burn out. (by the way, I managed to sell the old reflectors with the bulbs and my old HID kit for $100. Score!)
 
Well sure, if what you wanted is just whiter light, that's a solution. Blue tint reduces luminance by cutting red light, and they compensate for that by running filament hotter.
To a degree, of course. Around 4300k is optimal for light output, which is why manufacturers stick with that figure. 5000 is basically pure white (looks best imo) with a minimal sacrifice in output. Everything above that is rice.
 
And here i'm silly and bought bulbs that give yellow light... :p

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And here i'm silly and bought bulbs that give yellow light... :p
I've been looking into this lately. Strictly in terms of temperature, yellow is good for fog lights, as it's the most visible from outside (other than red but there are obvious issues with that). For headlights, again, can't beat 4300k HIDs.
 
I've been looking into this lately. Strictly in terms of temperature, yellow is good for fog lights, as it's the most visible from outside (other than red but there are obvious issues with that). For headlights, again, can't beat 4300k HIDs.

They say it's better in fog with yellow light, doesn't reflect as much or something.

But all i know is that it's something the French used a lot... no idea why...

Edit:

Looked it up. Because war.

http://www.french-cars-in-america.com/why-did-france-have-yellow-headlights
 
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They say it's better in fog with yellow light, doesn't reflect as much or something.

But all i know is that it's something the French used a lot... no idea why...

Edit:

Looked it up. Because war.

http://www.french-cars-in-america.com/why-did-france-have-yellow-headlights
We just had this discussion recently in Random Thoughts. Basically, yellow doesn't offer better visibility for the driver in fog or mist or other inclement weather. However, it can make you more visible to others (again, red is even better but yellow is the best we can do).

IMHO, an ideal setup would be 4300-5000 headlights with 3000-3800 fog lights.


Edit: Just don't go full-retard.

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Edit: Just don't go full-retard.

477uzrc.jpg

This is acceptable in Minnesota. When there is purple rain outside, your radio blasts Prince, and your headlights are purple it creates a combination that offers perfect vision. ;)
 
Or to be more specific - is there a realistic chance a 55w halogen bulb can melt the plastic connector on the harness just because of difference in color temperature?

Basically, no. By the late 1990s, the running standard for bulbs in cars was often up to 55/65W (or the reverse) and connectors were usually specced to handle this correctly. For all practical purposes, if your 55W bulb rating was accurate, it doesn't really matter what color the light output is with regards to connector melting. The operating temperature difference just isn't that great and there is enough variance in the operating temperatures of 'white' 55W bulbs alone that other color bulbs' inherent temperature difference doesn't signify.

- - - Updated - - -

Thanks for the explanation.

Yeah, I've heard that about the blue tint bulbs, but I compared them last night and the marketing is correct - in terms of light output they are on par with a generic bulb (at least visibly, you can't tell the difference).

Set up a test range and see how far down the road they let you see vice standard bulbs of comparable tech. You might be surprised.
 
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