Headlight bulbs – general

All over the bike forums there seem to be people asking about LED headlight bulbs at the moment. We are not talking sidelight/parking light/running lights etc these are easy to change to LEDs and, as they are visibility lights and you don’t need to use them to see the road ahead, they do not need to be anything special. We are talking about headlights, dip beam and main beam, the things that you use to see where you are going.

Halogen Headlights.

Most modern vehicles these days use a light bulb known as a HALOGEN. The halogen bulb has been around for many years and has been developed to what is now the pinnacle of its efficiency. Most single filament halogen bulbs consume 55 watts of power and put out around 1400 lumens of light. They are very cheap to buy and produce, and are great value for money. The halogen bulb is on its last legs development wise and is probably the best that it is ever going to be. Some manufacturers are claiming all sorts of magic things for their bulbs (130% more light is one) but there is very little difference between the bulbs and you would probably need electronic equipment to see that difference. In conclusion, buy a halogen bulb from a known manufacturer and you will have the best available. Before you go out and buy 100 watt versions of halogen bulbs, remember that watts is the power consumed and more of that extra power will turn into heat than light, so for 90% more electricity, you may only get 25% more light, but enough heat to melt the wires on your bike! The second bulb from the left in the picture below is a 55 watt halogen bulb with a H11 base as fitted to many Ducatis.

bulbs1

The first bulb (left) is a 35 watt HID xenon with a H1 base, The third is a COB LED with a H11 base, and the right hand one is a SMD LED with a H1 base.

LED headlights.

The LED bulbs above (the two on the right) are absolutely useless as a headlight bulbs. They would be fine for a show bike that never goes on the road, but will not give any decent light to light a road ahead. The COB LED uses about 8 watts of power, but at a guess only puts out around 500 lumens. The other LED (on the right) will use about 2 watts of power and puts out as much light as a dead glow worm.

If you want LED headlights then be prepared to spend the money on complete LED headlight units as LED bulbs in halogen reflectors just do not work. Manufacturers like BMW and Ducati motorcycles, and Seat, VW, Audi, Mercedes cars all make LED headlights but they are designed to be LED headlights and are completely different to anything else. These are being fitted to save electrical energy and improve longevity rather than to boost light output.

HID xenon.

These are the headlights that are often seen on upmarket cars. They consume 35 watts and have a light output of around 3000 lumens, over twice as much as halogen bulbs. The downsides of HID xenon lights are that they need a ballast fitting to fire them, see next picture, and they need to be fitted into projector headlights to control the amount of stray light and avoid dazzling other drivers. Both my Ducati ST2 and the 848 have projector headlights as standard. Projectors can be identified by looking at the front of the headlight and seeing what looks like a round magnifying glass. The projector has a physical metal shield inside to provide the sharp cut off required. The lack of this shield and the subsequent stray light is the reason that HID xenon bulbs should never be fitted into normal reflector headlights. When they come towards you at night you will sometimes see HID xenon lights as blue, they are not blue as standard, but the blue light in the visible light spectrum bends more than the other colours, so the blue is the first colour that bends around the edge of the metal shield in the projector. Below is a picture of a modern HID ballast.

ballast

If you retrofit HID xenon lights to your projector equipped Ducati then you will have to find room for this ballast. It is about 2 cms thick. These lights use less power than standard lights so would put less strain on the bikes electrical system. Some people think that a relay should be used with this, but after some experiments with starting and running these units I have come to the conclusion that a relay is not needed, if you use an inline fuse then a 5 amp is fine for each ballast.

Bulb bases.

In the pictures above you will see that there are two different bases on the bulbs, H1 and H11. These have nothing to do with the light output of any bulb that is fastened to the base, it is only the fitting of the bulb to the headlight. I have shown the H1, H3 has a small wire tail and is used in some headlights and many foglights, H4 is a twin filament bulb for dip and main beam in one bulb but with a large base, H7 is a more modern fitment used on some BMW bikes, and other things, H11 is used on the 848. There are more but a Google image search will show you those.

I made a little video today to illustrate the difference between the LED and the HID. Both bulbs are on in the video but I then put a bit of card over the HID light to show what the beam looks like for the LED.

This one shows the lights from the front. This proves that LEDs are great to be seen with but not for seeing the road with.

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One thought on “Headlight bulbs – general

  1. Dave Leslie January 28, 2016 / 11:54 am

    Good article Bob, puts it all in layman terms.

    Like

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