A 4-Part Series to Clue you In before you Buy

Week 4 – Optics and Electronics

So here we are, coming to the end of our crash course on everything you need to know before buying a light bar or driving lights for your 4WD. Hopefully you’re feeling more clued in and confident, and are nearly ready to pick out your new lighting rig.

This week we’re looking at the optics, colour temperatures, LED chips and light electronics. These are the last four areas that you should understand before setting about finding the perfect lighting rig for your vehicle. So, without further ado, here we go.


We briefly touched on optics in week two, when we were discussing how lumen values actually work in real world conditions. An LED produces a fixed amount of light. How that light is used is what will determine how well a light bar or driving light will work on your vehicle.The optics of a light refers to how the design of the light uses reflectors to change the direction and intensity of the light that it puts out.

Manufacturers use a whole range of different methods—there’s no right or wrong way here. What matters is the on-the-road result. This can be measured by looking at how far and wide the light is spreading, the wattage,  and the lux measurements that we covered earlier.

Colour Temperature

Colour temperature is measured in Kelvins (k), a thermodynamic temperature scale. To make it a lot less complicated, a candle is 1500k. Daylight is about 5000k. Headlights start at about 4000k, and range up to 8000k. Anything above 6000k is blue light, and often illegal (and unnecessary). The accepted sweet range is 5000-6000k, for balancing definition and clarity.

If however, you want a ‘warmer’ hue, many people opt for the 4000k range. These lights can be very useful, particularly where there is a lot of mist and fog. The more yellow light penetrates the fog without reflecting back, allowing you to see further while avoiding getting blinded by the glare.

Some manufacturers now offer 4000K as a standard option, specifically for this reason. This allows users to have the advantages of solid state LED technology but have the benefits of a yellower, warmer  light. This is very much a personal preference, and a decision you’ll have to make on your own.

LED Chips (unfortunately not edible)

As I mentioned in Week 3, the LED chip is the central component of an LED light. They are what converts the electrical energy into light.

There has been lots of innovation in this field in the last few years, with companies like Cree, LG and Lumiled battling to produce the most efficient LED chips. In fact, Cree once dominated this market entirely but now many manufacturers are producing their own in-house chips.

The main things that are to be considered with LED chips are light output, longevity and effects of temperature. As the technology has developed, the wattage value of chips has come down. Traditionally, a 10 watt chip was considered to give the best size to output ratio. Recently however, 5 watt chips have improved in quality significantly and are now the preferred choice.

The reason for this preference is that the 5W chips dissipate heat better. 10W chips can create a hotspot which means that the light is more difficult to spread and the lamp cannot be worked as hard. However, as usual, the main deciding factor is cost. 5W chips are easier and cheaper to produce, and if they perform as well, if not better, they’re the obvious choice for manufacturers to use.


Here, we’re referring to the unseen but vital inner workings of your LED light bar or driving lights. While they may not be visible they are absolutely integral to performance, and should be of only the highest quality.

Some manufacturers opt for cheaper components, and this may be reflected in the cheaper overall cost of your setup. These components will be unable to withstand high temperatures for long periods without failing. This mightn’t be a problem if the light is only used briefly every once in a while. But the last thing you want is for your lights to start failing you in the middle of an overnight trip in the middle of nowhere.

The first signs of failing electronic components is dimming of your lights. As the LEDs in your lights are usually grouped in mini-systems of 3 or 4 bulbs, you’ll notice one of the groups going out, rather than the whole light.

A good light should also have a temperature control built in to the design. This system will automatically reduce the power to your lights if they get too hot, thus saving them from permanent damage. Once the lights cool down enough, the system will automatically return the lights to full power. Having your lights on whilst idling is a surefire way to build up heat quickly. Without a temperature control system, they’ll burn out in no time.

If the light manufacturer doesn’t specify whether they include a temperature control or not, just ask. Also, always check the fine print of the warranty to see if you are covered against overheating of the lights (it’s a very common problem). It can be very frustrating to burn out your new lighting rig by forgetting to switch them off when you’re stopped.

The Wrap-up

So there you have it, our guide to the most important terminology and jargon you’re going to encounter when researching a light bar or driving light setup for your vehicle. Hopefully we’ve left you feeling much better equipped to tackle the often confusing world of auxiliary vehicle lighting.

The perfect lighting rig for you is out there, now it’s time to go out there and get it! Armed with all your newly-learned knowledge you’ll be able to make the best decision and be blazing up the trails in no time.