Reply With Quote
The link below is to a picture of the Philips D2S bulb that is the OEM bulb in my LR3 HSE but is not the same bulb as in the D4/LR4 HID Xenon headlights, (uses D3S as below). OEM for the 3 might actually be OSRAM Xenarc 66240 but that part number is the same as the Philips. The D2S bulbs are rated at 35 watts and 85 volts as they are ballast operated and that is the expensive item relative to the bulbs. The D3S bulbs are the same 35 watts, but run at 42 volts.
The colour temperature of the OEM lights is 4300K per the Philips 85122 bulbs below. Sometimes you will see a + sign following the part number and that infers that the bulbs are colour matched at time of manufacture.
There is an argument to say that when one side burns out, that both bulbs should be replaced so as to match the colour, as with use, the projected light colour changes over time so the recommendation is to change both.
My wallet says otherwise.
The "bi" in bi-xenon refers to the internal design of the head light assembly and means that the assembly, (the bulb does not care), is both high beam and low beam. In the case of our Land Rover "projector" lights, (the round glass globes with the Fresnel surround), this means there is a mechanical flapper, (shutter is the preferred word), that lowers to provide both high and low beam and then pops up again to block off the high beam light rays so that oncoming traffic only sees the lowered beams.
People who design illumination systems regard the 4300K colour as a good compromise to provide what is called definition. This is effectively the ability to actually determine what an object being illuminated probably is. The more blue colour bulbs, say 5000K and greater, result in a reduction in the ability to distinguish detail, (regardless of brightness), of the object being illuminated. Effectively, you can see the object but you cannot quite figure out what it is. This is because the more blue frequencies means there are fewer other frequencies of light that allow our eyes to actually define what an object really is.
This applies to clear conditions; for rain, dust, snow, fog, etc, then the yellow 2500K is preferable. More contrast is provided, and there is less back splash of light off the air particles. That is why I installed the 2500K H11 yellow bulbs in the bumper located snow lights.
As well as from the dealer, the Philips D2S lamps are available on eBay. There is some question as to what one is actually purchasing of course; a generic bulb in a fancy box or the real thing. I do not think there is any way of really knowing as it seems the copy gurus are getting better at spelling.
I purchased a pair from a BMW guy off eBay who removed them to install blue coloured non OEM Xenon. There is quite a bit of that gong on here in the New World; I think I was the winner in the deal however but I guess blue HID in a BMW make the chick magnet work better.
Originally Posted by Redback
Bookmarks