Sorry this is a little long
several posters are altering their headlamps in an effort to reduce the wattage. This is short sighted (no pun intended).
1. it's illegal
2. it provides worse and dangerous lighting.
I had done this research a yr ago for hidplanet.com, a hid retro fit website/forum. Also posted it at FreshAlloy.com.
A popular mod or upgrade today for many owners is in lighting. Specifically Headlamps. HID conversion kits are all over the internet and with prices starting at $40 and claims of ‘increased frontal lighting’, it’s hard not to jump in with both feet.
But are your really getting better lighting?
A recent thread at HIDPlanet.com got me thinking and researching what happens when HID bulbs are installed in headlamps designed for halogen bulbs.
I gathered a lot of my facts from the following site:
http://www.danielsternlighting.com/t...nversions.html
If you want the full test results they are linked at that site in PDF files.
1. It is important to understand that headlamps are designed to meet govt standards.
How ever, each manufacturer goes after those standards in their own way. We see this all the time in various parts of the automobile.
Car manufacturers (since the demise of the sealed beam headlamp) have used 4 basic concepts in meeting the headlamp standard. they use:
Halogen bulb w/ reflector lamps
Halogen bulb w/ projector lamps
HID bulb w/ reflector lamps
HID bulb w/ projector lamps
Each lamp is computer designed around the exact type of bulb and the bulbs can't be swapped back and forth..here is a generic example of a projector lamp:
2. HID bulbs and Halogen bulbs create two completely different light sources.
A hid bulb has 2 hot spots at each end of the light.
a halogen bulb only was one.
since the hot spots are in different locations and generate light completely different, an hid bulb won't work in any halogen lamp (reflector or projector) because the light will hit the inside reflective bowl incorrectly. These hotspots are designed with tolerances in the ½ mm range. As you can see in the picture the HID bulb on the left has it’s hotspot 2mm off from the halogen bulb.
http://www.danielsternlighting.com/t...nversions.html
"A halogen bulb has a cylindrical light source: the glowing filament. The space immediately surrounding the cylinder of light is completely dark, and so the sharpest contrast between bright and dark is along the edges of the cylinder of light. The ends of the filament cylinder fade from bright to dark.
An HID bulb, on the other hand, has a crescent-shaped light source -- the arc. It's crescent-shaped because as it passes through the space between the two electrodes, its heat causes it to try to rise. The space immediately surrounding the crescent of light glows in layers...the closer to the crescent of light, the brighter the glow. The ends of the arc crescent are the brightest points, and immediately beyond these points is completely dark, so the sharpest contrast between bright and dark is at the ends of the crescent of light.
This diagram shows the very different characteristics of the filament vs. the arc:
The HIB bulb on the right creates 3-5 times more light. While this is a good thing in a properly designed lamp, it is a very bad thing when put into a lamp designed for a halogen bulb.
3. Part of the Standard 108 that directs the Optical Lamp Engineers is Safety, for the driver and other drivers . And is a major driving force in the design and bulb choose.
Lumination in the proper places is a major consideration.
light is designed to be in the correct places so your eyes don't get tired or fixated on a particular spot. There is also concern that the distance light fades properly. And that the foreground light is not too bright.
I have taken the reports from the above site and created a condensed version (see repots at website for FULL disclosure)
This report is for:
US Dept of Tran., Natl Hwy Traffic Safety Adm
Office of Vehicle Saftey Compliance
Federal Motor Vehicle
Safety Standard 108
Lamps, Reflective devices and assoc eq.
here is the test result. They tested a ORSRAM(a name brand) XENARC D2R 35w. in a halogen reflector lamp.
I have posted the correct halogen bulb results next to the PnP hid results:
THe hid name brand bulb failed in the halogen designed lamp. At some points the light is 20 times too bright!
Here is a visual color chart of the passed bulb and the failed bulb:
Here is another test result from the same web page:
These charts make it very easy to see why ‘converting’ to an hid kit in any halogen designed lamp is just wrong.
the light is all over the place.
Just because there is a Plug n Play Hid conversion kit listed for your headlamp does not mean that it works properly.
Any Hid will make more light that the Halogen lamp is designed for.
Light's effect everyone else on the road. They are designed not to create burn spots in the retina of the other driver. When putting an HID in the halogen lamp you are effecting the safety of the other drivers.
The fact is that any modification of headlamps is illegal. And for pretty good reason.
Here are pictures of a maxima halogen projector lamp with a HID conversion kit:
Notice how uneven the light is.
Here is a picture with the correct halogen bulb:
One of the most important features of a lamp designed for an HID buld is the cut off. It creates the flat line across the light. WHY???? because the hid in a properly designed hid housing can still be too bright for oncoming traffic!!!!
SO if your halogen headlamp doesn't have a cut off, it fails there also.
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