Comparison between LED, HID and Halogen - What is the difference?
Not all that long ago most vehicle-mounted lights were based on halogen technology. In the 1990s HID lights started to appear, at first as fitted headlights on some vehicles and then as after market accessories. Both types have their advantages and disadvantages, like any technology tends to do, and both had their fans and critics. In the last few years another type of light has started to take over the market; that's LED lights. They're becoming extremely popular because they avoid most of the drawbacks of the earlier types while having a few unique advantages. If you're wondering what the differences are, here's a quick guide to all three kinds of light along with their plus and minus points.
Halogen lights are very like a standard light bulb. They contain a thin wire filament which heats up and glows when an electric current is run through it. The difference is that the lamp is filled with a halogen gas, usually iodine or bromine. In a normal bulb tungsten is gradually evaporated from the filament, weakening it; this is why it eventually burns out. The evaporated tungsten is also deposited on the inside of the bulb, forming a thin film that blocks some of the light. In a halogen lamp the gas sets up a chemical reaction that deposits the tungsten back onto the filament; this gives it a longer life and also keeps the bulb clear.
There are problems with halogen lights, though. Although the light they give off is whiter than a normal bulb it still has a noticeable yellowish colour, and this isn't idea when you're looking for good visibility at night. The lamps are also sensitive to vibration and travelling over rough ground can break the filaments. Their lifespan is a bit limited too - between 500 and 1,000 hours is normal. If you have halogen lights on your vehicle don't go anywhere without a supply of spare bulbs.
High Intensity Discharge lights are also known as Xenon lights. They initially appeared as headlamps on high end cars, with the 1991 BMW 7 Series being the first to use them, but quickly became popular as add-ons. They work by evaporating metal salts inside a chamber filled with xenon gas, then igniting an arc between two electrodes. This produces a very intense light that's a lot whiter than the beam from a halogen lamp. Because there's no filament they resist vibration and jolts a lot better than halogen lamps do. They're not perfect, though. They run on high-voltage current, so they need a current control device called a ballast as well as a high intensity spark generator to ionize the xenon gas. They're also expensive. A typical HID light has a lifespan of about 2,000 hours.
Light emitting diodes, in our opinion, are the best lights you can currently get. They're almost as bright as HID lamps and because the colour of the light can be controlled a lot more carefully they give better visibility. LED lights producing daylight-like white light will show you the ground ahead better than anything else on the market. They're electronic components which generate light by dropping electrons to a lower energy level, and because this is so efficient they use a lot less power than either halogen or HID systems. They're also completely solid state, so they're almost completely immune to rough treatment. Their lifespan is maybe the best news of all. A good quality LED light will last for up to 50,000 hours, so the chances of you needing to replace it because of failure are not high.
This is just a brief guide to the main differences between light types. If you want to know more we have plenty of more detailed technology articles here for you. If you want to keep it simple, though, just remember our advice and stick with LED lights. You won't regret it.