# HID lights



## robhoare (Jul 28, 2008)

Does anyone know how the self adjusting HiD lights work??? mine is UK spec56 plate aventura


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## robhoare (Jul 28, 2008)

In my manual it says according to UK law they must be auto adjusting but no ideas how, so come on some one out there must know how? also why do they sort of flash when they start and then turn different hues before going white? do they warm up or similar?
Rob


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## roj1943 (Aug 10, 2006)

Hi Rob
The short answer is that they are illegal in the UK unless fitted by the car's manufacturer complete with auto levelling and headlight washers. Auto levelling would not be an easy thing to do yourself unless you can find a specific kit made for the job. Effectively it does what the little manual headlamp levelling wheel does, but it needs level sensors and some electronics to make it work. Google HiD lights and you will find a lot of info.
Roger.

PS They get brighter 'cos they are arc lamps with a soft start.


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## robhoare (Jul 28, 2008)

no its a factory fited thingy i was just wondering how they auto leveled, this arc lamp bit - does that mean no filament as such? just spark and igniting gas?

Sorry I'm thick

Rob


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## roj1943 (Aug 10, 2006)

Hi Rob
I'm no expert, but I just Googled HID lights. Here's a quote:
"The HID bulb itself is similar in basic design to traditional HID lamps (a common example being the fluorescent tube used in interior lighting). Two electrodes are sealed in a quartz envelope along with a mix of solids, liquids, and gasses. When cold, these materials are in their native state (at room temperature) but are mostly gases when the lamp is hot. Starting of these lamps may require up to 20 KV to strike an arc but only 50 to 150 V to maintain it. Lamps may be designed to operate on either AC or DC current depending on various factors including the size and shape of the electrodes. A unique set of ballast operating parameters must be matched to each HID bulb.
Of all the problems that had to be addressed for HID headlights to become practical (aside from the cost), the most significant was the warm-up time which was solved by programming the controller to deliver constant power to the lamp rather than the more common nearly constant current that would be provided by a traditional ballast. With this twist along with a special lamp design, the lamp comes up to at least 75% of full intensity in under 2 seconds."

And another:
"Clearly, these lights can be fitted to any car but the law requires any such car to be fitted with either a headlamp beam adjuster or self-levelling suspension."

Just type "HID lights for car" into whatever search engine you use, and you will get more information than you could ever need.

Have fun
Roger.


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## mapengo (Aug 31, 2008)

*The law regarding HID in the UK*

Hi Rob, All interested parties.

See this from the DfT website 
Department for Transport - Aftermarket HID (Xenon) headlamps


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## aussietrail (Sep 24, 2004)

mapengo said:


> Hi Rob, All interested parties.
> 
> See this from the DfT website
> Department for Transport - Aftermarket HID (Xenon) headlamps


I find this ruling very ambiguous and un-clear. They talk about the HID in general terms yet they're forgetting to clearly mention the type of HID bulbs being used. The issues they raise in their statement regarding glare and un-even light pattern was indeed present with the older type HID kits which use a dual core bulb technology, however this was long overcome with the introduction of a single bulb technology which uses the same bulb for Hi and Lo beam and the cut-off line is VERY precise with no glare whatsoever.


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## mapengo (Aug 31, 2008)

It would be surprising and maybe disturbing to see clear and unambiguous policy from a government dept. 

It's not surprising to see policy failing to reflect the actual situation on the ground, given that technology is clearly moving faster than the regulating body/s can act.

Nonetheless, this statement is pretty clear regarding the DfT's stance re aftermarket HID, and it does give the aftermarket boys a loophole within which they can legally produce aftermarket HID kits, albeit in the form of complete lighting systems.

Funny old world..


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## aussietrail (Sep 24, 2004)

In Australia it is even more funny LOL 

If you're a retailer selling HID, it is illegal for you to sell the HID kit and have it fitted to a brand new car that has NOT been registered yet (meaning a car at the dealers) but there is no problem whatsoever selling and fitting the exact HID kit to the same car AFTER it has been registered....Go figure! LOL 

My take on all these useless rulings is to carry the original bulbs in the glovebox compartment and if for some wierd reason, I do get pulled over by some dreaming cop who has nothing else better to do than look at the headlights of the oncoming traffic, I will simply say, I am only testing this kit and here are the original bulbs


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## robhoare (Jul 28, 2008)

yeah but how exactly do they auto level ?????- do they have some sort of gyroscope?

also found it interesting that HiD xexons must have an auto cleaning thingy by law wether its wipers on the lamps or water squities....!!


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## roj1943 (Aug 10, 2006)

Hi Rob
I have had no experience with self levelling suspension or headlights, but a little thought leads me to make the following comments.

Cars with auto levelling suspension are not kept at right angles to the Earth's gravity which a gyroscope would do but simply kept parallel to the road. Imagine going up a very steep hill with a gyroscope controlling the level. The car's rear wheels would be several feet off the ground! Think about it!

All you would need to do to keep a car level, ie parallel to the road, is to measure the angle of some suitable suspension component. If you load the rear of a car (say) and the rear then dips, the suspension must have moved. Measure how much and use hydraulics to raise the suspension to suit. Self levelling headlights could, presumably, use a similar system.

I was not aware that X-trails had self levelling suspension so if that is what you have, I would appreciate some details so I can go to my dealer and ask why he didn't tell me so that I could have had one!

Roger


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## robhoare (Jul 28, 2008)

nooooo its just the lights that self level just wondered how thats all! I had self leveling on another car - that was cool but i kept waiting for it to go wrong - i'll stick with the x's current suspension it seems a really good ride and quite good off road too...


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