4WD MODIFICATIONS - ELECTRIC & LIGHTS
No 4WD wagon or ute comes with lights that are adequate for night time bush driving. For that work you’ll need upgraded lighting.
The starting point for lighting improvement is the standard headlights. Over the years we’ve replaced the stock headlights
of many 4WDs, because the standard peepers are too dim for back-roads driving.
Improving your standard headlights is essential before fitting spot lights, because if you ignore the headlights and go straight for spotties the contrast between low and high beam is too great.
When you have to drop from your spottie-enhanced high beam to low beam the change in light intensity leaves you virtually blind for a few seconds, until your eyes adjust.
When headlights were one-size-fits-all, round or rectangular units it was easy to replace them with after-market lights that had better reflector shape and finish, and more refined lens optics. Light quality is brighter than standard and the beams are better focussed. You can still buy these replacement units for older 4WDs, from Narva and Hella.
The replacement kit usually comes with a plug that connects directly to the original terminal, so it’s simply pushed in and the replacement lights can be positioned and screwed home. Another option is to go for a sealed beam light, rather than the rear-insert types – many off-road competitors use sealed beams – because they can’t get ruined by water entry. The problem with sealed beams is that if you break a lens you’re up for a complete unit.
New 4WDs – even utes – come with custom-designed headlight assemblies that are unique to each brand and there are no replacement upgrades available. However, it is possible to upgrade the globes. High-performance halogen globes replace existing bulbs and are claimed to cause no problem with overheating polycarbonate light assemblies.
Halogen globes come in little boxes and it’s important that you don’t touch the glass with your fingers when you’re fitting globes to lights.
It’s also possible to convert those almost-useless, under-bumper fog lamps into driving lights, by replacing the stock items with compact spot lights. If you take that route, be sure to wire them through the high beam circuit.
Some 4WD owners convert conventional headlights to HID xenon, gas-discharge or LED lights. The light output from conventional halogen, or xenon-filled filament globes is typically in the 800-1200 lumen range. True LED and xenon products start at 3000 lumens and go up from there.
However, to be legal an HID or LED headlight must have some means of self-levelling and a washer system, so as not to dazzle incoming drivers and other road users. If you don’t have those features your installation is illegal.
Replacement halogen headlight globes
Many halogen headlight globe makers produce ‘performance globes’, promising added lighting output over standard globes. But how is this extra light output achieved without compromising reliability for the longer term? There is a compromise.
Regardless of who makes them, all halogen performance globes achieve their extra light output by being pushed beyond standard-globe operating tolerances. Without design improvements over standard globes they would face a severely reduced life, possibly only lasting for several hours.
To guarantee globe life, performance globes compensate for the additional load on the filament by introducing special gases such as xenon into the glass bulb to project the filament from premature failure. While this protective measure is effective, it will still not produce the life expectancy of a standard halogen globe.
The OEM globes fitted to vehicles are normally long-life types, because manufacturers opting for longevity rather than the highest level of light output, to minimise the replacement of globes under warranty.
So, higher performance comes with the compromise of reduced globe life, but there are other factors that affect the longevity of performance globes. Many of these factors are related to vehicle design.
Alternator output varies among auto manufacturers. Many modern cars and trucks with additional electrical loads from advanced multimedia and infotainment systems and on-board computers are typically equipped with alternators that produce higher voltages.
The downside is that as performance globes are already operating at higher-end tolerances, even small increases in voltage can lead to blown globes. To put this in perspective a five-percent increase in voltage can reduce the life of a globe by up to 50 percent.
Excessive heat is the enemy of most automotive components and in the case of performance globes, the heat build-up in a headlight housing can increase the filament temperature, leading to reduced life.
Unfortunately, modern 4WDs are equipped with smaller, encased headlights which make it more difficult for heat to dissipate efficiently. Space within the engine bay or body of the vehicle is also limited, further adding to the issue.
They might be convenient, but lights that turn on and off as a vehicle enters a tunnel, multilevel carpark or even in cloudy conditions can reduce globe life. Every time headlights are activated, a short term ‘surge’ is experienced by the globe during filament heat-up. The greater the number of on/off cycles, the increased likelihood that globe longevity will be compromised.
A problem particularly for 4WDs that regularly travel on rough secondary roads is vibration. The vibration from corrugated roads and rough shakes up most of the vehicle’s components, including the delicate globe filaments.
Increasing globe life
It’s recommended that you wear gloves when fitting any type of halogen globe, to avoid bare skin touching the glass section of the globe. When the glass is touched during installation, the residual oil from your fingers creates a ‘hot spot’ on the glass surface, resulting in uneven heating. If the glass doesn’t heat evenly, areas of the glass will be prone to higher mechanical stress, resulting in eventual cracking.
A loose terminal connector at the pins on the globe can result in intermittent operation, triggering light-up many times more often than with the automatic headlight scenario.
Additional heat generated by the bad connection can also transfer to the filament.
Faulty relays can also have a similar result.
What life to expect from performance globes
As with other automotive components, the old adage holds true: ‘You get what you pay for’.Premium-brand products normally provide better performance and longevity than cheaper parts.
The globe type also plays a role. From H7-type globes you might expect around 550 hours of performance, while for H4 globes which feature a dual filament, up to 900 hours is achievable.
Replacing globes at intervals should be considered as part of ongoing vehicle maintenance such as replacing oils, fluids, filters, brake pads, shock absorbers and tyres.
Our auxiliary light tests over the past few years have shown that price is a poor guide to buying spotties, because many of the most expensive lights on the market performed ordinarily and some of the cheaper ones performed brilliantly. Looking at a light will tell you if it’s well made and if its mounting bracket is substantial, but won’t tell you much about its performance.
Driving lights, or pencil beams as they’re often called, usually rely solely on reflector shape and finish for their beam direction, and have a plain lens.
Spread-beam lights use shaping of the lens – seen as fluting or bars moulded into the glass – to bend the light from the reflector into a shorter, but wider shape. The best combination is a spread-beam with a pencil-beam.
Spot light housings are either of plastic or metal construction and, generally speaking, metal lights are stronger than plastic types, but they’re more corrosion-prone.
The durability of plastic lights has improved in recent years and we’ve found that correctly-mounted plastic lights survive demanding off-road work without damage. However an angled stone strike can destroy a plastic housing.
The trick with light locations is to make sure the lights don’t stick out in front of the bull bar, or above it, where branches can smack them.
The ultimate driving lights are xenon, gas-discharge HID types and LEDs, but at the current stage of development they’ll set you back $500-$2000 the pair. Light bars are increasingly becoming more popular and the price range is $350-$1500 for quality units.
Many lights have foot mountings that are very difficult to adjust once they’re in place, so it’s important that you check adjustment access on your bumper or bull-bar, before buying a pair of spotties.
Low-profile bars often cannot accommodate large lights inside the bar ‘envelope’ and vehicle registration authorities are getting testier and testier about lights and brackets that protrude beyond the bar profile.
Watts and Volts
Most auxiliary light buyers – and light sellers, for that matter – rely on the wattage rating of a driving light or spread-beam when buying after-market equipment.
If vehicle lights were similar to household lights that would be a reasonable procedure to follow, but vehicle lights differ in a very significant way from house lights.
When you buy a new globe for your house, you don’t expect it to be ‘directional’, but vehicle lights need to be directional, in a precise way, and that’s where the science comes in.
This directional component comes from the reflector – its finish and shape – and from the lens fitted to the front of the light, in addition to the light output from the globe. Our light testing over the past few years has shown that some halogen 55-watt lights are superior to 100-watt models and even130-watt models.
Relying on power ratings above 100 watts creates additional problems for the light designer and the buyer, including the need for expensive wiring and relays.
There is also the question of alternator capacity in a 4WD which might be fitted with a sound system, auxiliary radios, a portable refrigerator and other electrically-operated equipment.
This is where xenon gas discharge HID and lower-output LED lights come into their own, because they can deliver brilliant lighting from 35-100-watt globes.