Bi-Xenon blub question

[PobodY]

I'm sure that this has probably been asked before, but I couldn't find it when I searched. - Please feel free to point me in the right direction and/or delete this thread (preferably after pointing me at the right one).

In short: is the "Main-beam headlamp" blub in my car doing anything when I've got bi-xenons?

The back story is that a friend of mine was talking about upgrading the headlights in his new company car (A200 CDI I think) to either LED or HIDs, and it got me looking at mine. - The Xenon bulbs are nice and bright, but the little park lights look sickly and yellow beside them.

In preparation for replacing the side lights with LEDs (I will use the search function for recommendations) I was looking at the headlamps:
Sickly parking lights, bi-xenon on low, bi-xenon on high, indicators... and two H7 bulbs that don't seem to ever come on. - Thus my question.

 

[baxlin]

Not sure, but I don't think you'll have xenon high beam, as I understand they're not suitable for "flashing". The H7s will be your high beam.

But I maybe wrong........

Hopefully a guru will be along shortly.

 

[CabrioDave]

Not sure, but I don't think you'll have xenon high beam, as I understand they're not suitable for "flashing". The H7s will be your high beam.

But I maybe wrong........

Hopefully a guru will be along shortly.

Ah! PobodY: what happens when you try the flash?

 

[whitenemesis]

Bi-xenons lamps have a shutter biult in to mask the light output when dipped.

MB cars fitted with bi-xenons usually have a 'normal' halogen high beam lamp

When you flash your headlamps the halogen high beam comes on momentarily, something that would shorten the life of the xenon lamp/ballast

 

[stewslash]

Ah! PobodY: what happens when you try the flash?

Isn't that the whole purpose of bi xenon as oppose to a normal xenon is that they are used for flashing by means of opening a flap in the headlight allowing all the light to be emitted instead of the the cut off beam pattern ?

 

[PobodY]

Ah! Now that I didn't try. - I just did sidelights, then dipped, then main beams... and they didn't come on.

I'll have to wait for my wife to get home because I can't think of a way to flash the headlights and see it for myself... but I suspect the mystery is solved.

Why not flash something like the fog lights rather than include an H7 bulb that is only ever used to flash?

 

[CabrioDave]

Isn't that the whole purpose of bi xenon as oppose to a normal xenon is that they are used for flashing by means of opening a flap in the headlight allowing all the light to be emitted instead of the the cut off beam pattern ?

Bi-xenons take quite a while to come on, come to full brightness, and set their alignment. By then, whoever you were wanting to flash has passed by (or under ... )?

 

[stewslash]

My w204 with bi xenons flashes using the method I've described above , it also has a H7 in each headlight that is part of the cornering function of the intelligent lighting system

 

[whitenemesis]

Does your 204 flash the bi-xenons only when already illuminated, otherwise the halogens flash? As mentioned they take time to fully come on.

 

[CabrioDave]

Why not flash something like the fog lights rather than include an H7 bulb that is only ever used to flash?

Two problems:

Fog lights are specifically designed NOT to send light forward at face height (where it would reflect back to the driver, who can't then see much through the fog). The oncoming driver might be able to determine that the foglights have come on, but in daylight would have to be specifically observing them to notice.

In fog, with your fog lights on ... how are you going to flash?

 

[stewslash]

Does your 204 flash the bi-xenons only when already illuminated, otherwise the halogens flash? As mentioned they take time to fully come on.

No I've tested this , on start up with even without the lights on the headlight lenses do the normal pan side to side , centre then level
Flashing with no lights on it fires up the xenons
Flashing with lights on opens the flap inside
The H7's are for cornering only in conjunction with the panning the xenons

 

[b1g1an]

Bi-xenons lamps have a shutter biult in to mask the light output when dipped.

MB cars fitted with bi-xenons usually have a 'normal' halogen high beam lamp

When you flash your headlamps the halogen high beam comes on momentarily, something that would shorten the life of the xenon lamp/ballast

I have my lights set to always be on via the instrument cluster menu, poor mans day runners!

When you flash, just as when you put them on high beam normally, you get the shutters flip up on the xenons AND the H7s come on, it's a real wall of light and is much brighter than cars that use the bi-xenons on their own for main beam.