4WD MODIFICATIONS - ELECTRIC & LIGHTS
The black art of lighting up bush roads has produced a dazzling array of replacement and add-on equipment, which makes selecting night-vision aids quite a business. The good news is that prices have dropped.
The reason for buying replacement headlights and after-market lights should be to enhance standard headlight penetration, which is inadequate for driving on Australian country roads. Our laboratory and real-world light tests over the years have shown that price isn’t a reliable guide to light performance, because many of the most expensive lights on the market have performed ordinarily, while some of the cheaper ones blazed brilliantly.
Drivers used to have to spend around two grand for adequate bush road lighting, but these days, $400-$1000 can do the trick.
Looking at a light will tell you if it seems to be well made and if its mounting and adjustment bracketry is substantial, but it won’t tell you much about its performance.
The most confident light makers have supporting literature that shows approximate light patterns on the road surface and pattern distances in metres. However, such diagrams need to be scanned carefully, because light intensity is very difficult to quantify.
Narva Ultima MkII pair
The most widely accepted figure for useful light at a distance is the ‘one lux’ figure – sufficient light to read a written page – but many light beam charts quote ‘quarter lux’ distance; the intensity that will illuminate a ‘cats eye’ reflector.
The traditional auxiliary lighting choice is a pair of round spotties, but the development of light emitting diode (LED) lights has changed the need for that design. The world-first Hella LED driving lights of 2012 retained large reflectors with three LED bulbs, but subsequent developments have seen most LED driving lights take the form of multiple LEDs – typically 20 to 100 – set in small, individual reflectors.
Because each small LED module is housed in its own reflector, rather than relying on a large circular one, there is no advantage in having a circular housing. LED arrays can be arranged in traditional-shape, round housings, or in light bars, with single- or double-row layouts.
Let’s look at your LED lighting options, starting with improving your headlights.
Why some replacement LEDs don’t work well
Parallel with driving light changes are replacement bulbs, or full replacement housings, for halogen headlights.
Nearly all new 4WDs are available with LED headlights, either as standard or an option. That has spawned a thriving after-market industry in replacement bulbs for traditional halogen globes, allowing existing equipment to be upgraded. Sometimes that exercise works well and sometimes it doesn’t.
What many 4WD owners don’t realise is that simply replacing a halogen globe with an LED bulb inside a reflector housing won’t automatically guarantee improved illumination of the road, because of the different size and light properties of halogens and LEDs.
The light emitting section of a halogen globe is that small coil
The light-emitting coil inside a halogen globe is a tiny light source that radiates in all directions. The reflector is designed around the precise position of that omni-directional light source, to produce optimal high and low beams.
Unlike a halogen globe, an LED doesn’t emit light in all directions, but is directional. On the back side of an LED there’s no light. So, when designing an LED headlight replacement bulb, designers put two or more LEDs ‘back to back’. That’s still not omni-directional, but it’s better than a one-directional light.
That design is a compromise and there’s yet another. To replicate the small size of a halogen ‘hot’ coil the two back to back LEDs need to be as close together as possible, but that causes heat buildup. The best quality replacement LED bulbs use exotic, thin material between the two LEDs.
Cheap LED bulbs have fatter LED structure and that causes a ‘focus’ problem. The original reflector is designed around a small light source and a larger source can cause a blurred, weak beam.
Note the very thin sections at the tips of these LED bulbs
Yet another issue is the position of the LEDs in relation to the reflector. If the distance from the back of the reflector to the LEDs isn’t exactly the same – and we’re talking fractions of a millimetre here – as with the OEM halogen globe, the replacement LED bulb will not ‘reflect’ as designed.
If you’re buying a replacement LED bulb, take your standard halogen globe with you, so that you can replicate the position of the light source. Also, get an LED bulb with the closest back to back LEDS – the thinner the better.
Replacement LED headlight units
For similar money to the best LED replacement bulbs it’s possible to buy a pair of replacement headlights, if your older 4WD is fitted with ubiquitous seven-inch round headlights.
The reason there are so many seven-inch replacement lights in the market is because in the USA it was illegal to have any other sized headlight in any vehicle – car, bike or truck – until 1997. Although many different styles of headlights are now legal in the USA, many of today’s US trucks still have four seven-inch headlights.
We’ve evaluated several different brands of replacement seven-inch headlights and found that the quality and variety is as diverse as that in the globe replacement business.
We found that it pays to stick with established brands, including Stedi, KC, Narva and Hella. Some of the cheap, unbranded units we’ve seen have worse beams than the standard halogen headlights.
No matter what you do with your headlights, they won’t be adequate for lighting your way on Australia’s country roads. Driving lights are necessary and by far the most popular lights these days are LED.
Prior to that we had halogen and high intensity discharge (HID) globes in driving lights and these are still available. FRYLYT still makes halogen driving lights, but they won’t send us a test pair.
Lightforce makes a ‘hybrid’ HTX driving light that combines a ring of spread-beam LEDs around a long-beam HID centre light. We tested the original HTX1s and found them to have an excellent combination of spread and distance. The later HTX2s had less HID power and slightly shorter beam distance.
Lightforce HTX2 pair
Two years ago the HTX1s were a stand-out for distance and spread, but the latest all-LED lights, such as Narva’s Ultima MkIIs can almost match HTX2s, at a lower price than $1500 for a pair of the Lightforce units.
Narva Ultima MkII pair
ARB makes the Solis, adjustable-LED-output round driving light, for around $500 each, but they won’t lend us a test pair.
Down the price scale even further sit a raft of round driving lights and light bars. We’ve tested Big Red Gear’s new 2022 combinations of seven-inch and nine-inch round lights, in combination with the BRG 40-inch light bar and found these three-light combinations to be excellent value for money, at a total price of only $400-$500.
Stedi single ST3303 24-inch light bar
Stedi’s ‘Pro’ light bars are particularly powerful and a $470 ST3303 24-incher, or an $850 39-incher can light up the road very effectively, for less than a grand. The 39-incher pulls heaps of current, which isn’t a problem for larger alternators to handle.
Check out our recent video tests in this section of the website.
Yesterday’s halogen bulbs wear out, through the effects of filament degradation, vibration and the extreme heat of the bulb: around 400 degrees C.
Rough roads, poorly installed lights and clear plastic light covers used at low speeds, where there’s insufficient cooling airflow, all contribute to shortening of bulb life. In bush-travel conditions, a halogen 55W bulb may last for only 200 working hours, but a 100W bulb for as little as 50 hours.
HID lighting technology replaced the filament of the light bulb with a capsule of gas. The light emanated from an arc discharge between two closely spaced electrodes that are hermetically sealed inside a small quartz glass capsule.
To operate, HID lights require high-voltage ballast units that supply and maintain high voltage and control the current.
The amount of light produced is greater than from a standard halogen bulb, while the HID globe consumes less power. However, like halogens, HID globes eventually need replacing.
LEDs deliver bright, white, even beams and the best of them can turn the road to virtual daylight out to around 1100 metres.
Big Red Gear nine-inch pair plus BRG 40-inch light bar
Light Emitting Diode lights work completely differently from incandescent and HID lights, generating photons of light at the atomic level.
Low-energy LEDs emit in the infra-red spectrum and are used in appliance remote controls. Higher-energy designs emit light in the visible spectrum.
In most lights LEDs range from 5W to 15W output, so they’re arranged in multiples. LEDs rarely need replacing, unless damaged.
Comparing light output claims
Light engineers talk of colour temperature in Kelvin units. The typical colour temperature of a standard incandescent globe is less than 3000 Kelvin; a halogen globe falls into the 3000-4000 Kelvin range and HID and LED lights exceed 4000 Kelvin.
This is by far the most confusing of all light statistics, because it compares the Kelvin absolute temperature scale with the visible light spectrum.
William Kelvin was a physicist in the late 1800s and developed a temperature scale, using Absolute Zero (-273C) as its starting point, hence eliminating the minus numbers you get if the freezing temperature of water is used as the starting point. Scientists welcomed the Kelvin Scale, because calculations are much easier to do without minus numbers.
The same bloke heated a piece of carbon, noting that it changed colour as its temperature rose: dim red, bright red, dim yellow, bright yellow, yellow-white, bright white and blue-white. Kelvin temperature points were later added to colour-temperature charts.
Back in the days when light brightness was a function of applied heat – making a filament glow bright yellow to white hot, but stopping short of melting it – the scale had relevance. Back then, the higher the temperature, the whiter the light, but now there are cooler light sources – gas discharge (HID) and light emitting diodes (LEDs) – it’s plain confusing.
Checking out a colour temperature chart, it’s obvious that if you evaluate an HID or LED light purely on its colour temperature, more isn’t necessarily better. The ‘sweet spot’ is in the 4000-5500K region, because higher numbers give too much ‘blue’ cast and head for eventual darkness at the end of the visible spectrum.
Like using wattage to evaluate the useful light spread and penetration of a pair of driving lights, lumens and lux figures need qualification. Both measurement units indicate brightness, but there’s a catch. Sure, a light putting out 10,000 lumens has ample power and, if spread over an area of 50 square metres, a value of 200 lux, but if spread over 100 square metres the lux figure drops to 100.
Beware the light chart that displays beam shape and distance in intensity of only 0.25 lux. A much more accurate measurement of beam intensity is the Isolux system that measures beam distance at one lux intensity – sufficient light for reading small, printed text.