Comparison between LED, HID and Halogen
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 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 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.
LED Efficiency Compared To HID & Halogen
If you’re planning on adding an accessory to your vehicle you need to know how it’s going to fit in with the vehicle’s own systems and any other accessories you have. Obviously you also need to know that they’re going to do the job you want them for. That means you need to consider the power consumption, current requirements and the actual light output.
The wattage of a lightbar is the total amount of electricity it consumes. LED lights tend to have a much lower wattage than halogen or HID ones because LEDs are a lot more efficient at turning electricity into light; that means for the same light output as an old-style lightbar an LED one will be using up to about 80% less electricity. If you’re running lights with the engine off that’s good news for your battery.
You’ll also find figures for amperage in a lot of reviews. The amperage is the current drawn by the light and it’s pretty important to know. Your vehicle’s alternator can only supply a limited amount of current, and if the total draw of all your accessories and systems exceeds that you’re going to have problems. The good news is that most vehicle alternators have a reserve capacity of about 40% over their rating, so you have that much to play with. Just find out how many amps it’s rated at and multiply by 0.4; if you keep the total amperage of your extra accessories below that figure you should be fine. Of course you can always install a more powerful alternator if you’re starting to hit the limit.
Now on to the light output itself. Technically that’s known as luminous flux, and it’s measured in lumens. The science behind it is quite complicated but basically what’s being measured is the amount of visible light that’s radiated. The output of a light in lumens is used to calculate the actual brightness level it can create, which is measured in lux. If 100 lumens is projected onto an area of one square metre the brightness level in that area is 100 lux. Spread the same 100 lumens out over 10 square metres and the brightness level is only 10 lux. That’s why spotlights can light things up at a longer distance than floodlights can; they probably use exactly the same LEDs, but the spot concentrates the light over a smaller area.