HID conversion information.

The age old discussion of HID conversions goes on and on, So I thought I would put some facts together for people wishing to carry out this type of conversion.

Please don't flame this thread if you are a HID fan as it is all based on published research etc and opinions are based on facts.

The purpose of this thread is NOT to tell you what you should or shouldn't do, it is a thread that hopefully will give you some facts and opinions that you won't hear at the McDonalds car park meet. It is intended to give you information to help you decide whether it is worth doing and whether it comes with possible consequences.

We have all heard the "It's OK because I have fitted them and nobody has flashed me" and "It has passed an MOT so must be OK" type of arguments, but these are peoples opinions and are heavily biased towards the "I like them so will justify them" catigory.

So, lets dispell some myths first.


HIDs give much better vision.

Correctly designed HID can give better vision, but, many HID conversions only give you better vision in the foreground and can even give you less vision over distance. This plays up to a flaw in human perception. Illuminating the area directly in front of a car does make the driver feel more confident, but this brings problems as it actually reduces your night vision by closing down your iris to compensate for the bright light.
This effect can also be seen in people who swear that driving with foglights on gives them better vision. This is impossible over any usefull distance as the foglight is designed to give a low flat short beam. All it does is increase the illuminated areas around the front of the car, including the verges, in the same way many HID conversions do.
So, in effect, most HID conversions will throw less light into the far field and illuminate the near field more, creating an unjustified level of confidence and may increase the drivers confidence and speed.


HIDs are good for standard headlights.

This is simply not true.
The standard headlight optics have been designed to work with a halogen filament light source which has a standard, replicable focal point. In other words, if you fit a halogen lamp that is to the correct standard then the focal point, or point of light, is the same every time and this is very important for the beam pattern.
HID lamps have a very different focal point. Think of a normal lamp being a golf ball and a HID being a rugby ball. A different size and shape altogether.
You will hear people telling you that the beam pattern is just the same as normal as they have fitted them and have checked them. Not true as this is physically impossible. You may achieve a beam that is close, and it may even pass an MOT, but the beam will be different and can still cause nuisance to oncoming traffic.



HID conversions are legal.

This is another point that can be manipulated by people who want to have them.

The fact is that any HIDs are not legal in the UK by UK law. ONLY filament lamps are allowed by vehicle usage laws.
So, how come new cars have HIDs?
This is because UK law can be superceded by EU law and there is a document that allows HIDs to be used.
So, HIDs are allowed then?
Well, yes and no.
HIDs are only allowed over the UK regulations if they follow the EU law, and that is where the confusion comes in. The EU law states that the headlight unit must be designed for HID, have headlamp cleaning facility AND self levelling. It doesn't provide for aftermarket HID conversions, so the UK DfT interpretation is that HID conversions are only allowed IF they comply with the same specifications as factory fitted units.

I will add to this as myths and other bits crop up, but here are some sites and documents to read.

http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=1&cad=rja&ved=0CDUQFjAA&url=http%3A%2F%2Fassets.dft.gov.uk%2Fpublications%2Fdft-information-sheets%2Faftermarket-hid-headlamps.pdf&ei=oD7XULy_D-Kv0QXq-oHwDQ&usg=AFQjCNF1WC8dTWAGFHDcd9gBq3Qhidubsg&bvm=bv.1355534169,d.d2k

http://www.danielsternlighting.com/tech/bulbs/Hid/conversions/conversions.html


In the interest of fairness, if you do know of official and legal documents that say you are allowed to fit HIDs then please post them up, as I said this thread is to give relevant info to people wishing to fit them.

Please don't post what you think or what a mate says in a bar etc.

Also, it is worth noting that MOT regulations etc do not over write UK law. A point in the MOT guidelines does not have more weight than the vehicle usage regulations or DfT interpretation of the law. In an ideal world they would say the same though.


I have just noticed an increase in another negative side of HID aftermarket kits.

Most HID kits that people fit will be cheap Chinese kits and these can cause electrical noise due to cheap construction and lack of shielding. Several reports are floating around the internet of failures of critical systems, such as power steering, ABS etc etc.

At first this might seem a bit scaremongering, but, if you are an electronics/electrical based engineer you will know that noise on sensitive electronic systems is the work of the devil and can cause problems from spurious signals to total shutdown.

Most modern vehicles use what is called "Canbus" which is a data network that connects the whole system to the "brains" of the car. If this is disrupted then it is the same as disrupting your nervous system and can have unforseen problems.

Imagine turning your headlights on and all your cars warning lights come on and you lose your power steering. That is what has happened to a Mercedes owner that fitted an HID kit himself. When he took it to the garage they wouldn't touch it with the HID system in place.

http://mbworld.org/forums/c-class-w203/359793-c230-hid-installation-problem-errors-power-steering-failure.html

http://forums.audiworld.com/showthread.php?t=2790793

I looked at converting my F headlights to HID, but opted for TF projectors instead in the end


I have just ordered 4xHID front fogs.. Which will be cleverly wired up.. So that only 2 work off the front fog light switch...

Then with the switch flicked the other way all four will come on when the main beam is on.. I wanted front spot lights for night time B roads etc.. But didn't want it to look like a night stage rally car lol

cjj wrote: In the interest of fairness, if you do know of official and legal documents that say you are allowed to fit HIDs then please post them up

V5.

I really don't care, Jat has the which means I can actually drive her at night, which I cannot do with Madam as I cannot see jackhit on our country lanes with her lights ..

Clive why do you winge about HD's all the time

There are some points that should be borne in mind when thinking of a conversion...

1) Ask yourself why you want them. Is it because you want more light, or because you want to join the Barryboys in the "other" place? The reason for that question is the variation in colour temperature available. They vary from 3000K up to 12000K. The lower the colour temperature, the more yellow the light. 5000K seems to me to be much like English sunlight. After 5000K the light starts to become blue. 6000K is quite noticable to oncoming traffic. Any higher and you are asking to be pulled for a "look over".

The maximum light output comes from 4300K which is less yellow than tungsten, but still gives a useful visibilty benefit in bright light. I have 5000K on the bike and the lamp is difficult to see in sunlight as a result. I would have gone for 4300K if I knew why at that time.

2) HID lamps have a delay before they light up, a little but like domestic CFLs. For that reason, it is important to modify the circuit so that the dip beam remains on at all times. Otherwise, there will be a dark interval when changing main to dip. I believe this may in the regulations actually.


Although I agree that there is in theory, a regulation preventing their use, I would still recommend them. If we had all these petty regulations 100 years ago, we would never have sen the myriad of vehicle improvements. That having been said, make sure that the beam is set correctly and check what the beam pattern looks like. If it is scattering everywhere, put the bulbs back, as it will be useless to the driver and annoying to others. It is my understanding that projector lamps as fited to the TF will be quite good with HIDs. Certainly a Ford Puma with projectors produced a sharp and well defined beam.

jan its not the lights it your eyes my dear.couldnt resist that sweetie.have agrest christmas see you in feb

Bless really looking forward to it babe xxx

Softly~Softly wrote: Clive why do you winge about HD's all the time

I don't mind HD. In fact I have a HD telly in my living room, it is the HID conversions I don't like.

Jan, you have obviously not understood the point of the post. It seems you are the one "whingeing".

Leigh Ping wrote:

cjj wrote: In the interest of fairness, if you do know of official and legal documents that say you are allowed to fit HIDs then please post them up

V5.

Can you post a link?

dazlightyear wrote: jan its not the lights it your eyes my dear.couldnt resist that sweetie.have agrest christmas see you in feb

Snigger.

twice tonight I had to come to a sudden stop as I just couldnt see the road beyond oncoming HID fitted cars , both were OE fitment as well , the first was a new mondeo and the second a new merc , absolutely awful things !

AJL Electronics wrote: There are some points that should be borne in mind when
Although I agree that there is in theory, a regulation preventing their use, I would still recommend them. If we had all these petty regulations 100 years ago, we would never have sen the myriad of vehicle improvements. That having been said, make sure that the beam is set correctly and check what the beam pattern looks like. If it is scattering everywhere, put the bulbs back, as it will be useless to the driver and annoying to others. It is my understanding that projector lamps as fited to the TF will be quite good with HIDs. Certainly a Ford Puma with projectors produced a sharp and well defined beam.

This is why I posted this. It isn't a "don't do it thread", it is more to explain why the decision was made and to look at the physics and laws in place so that people can make their own mind up.