Propickup Digital Magazine
Issue link: https://read.dmtmag.com/i/94279
The diff erences between light throw and spread are clearly illustrated in this drawing. Note that fog lights throw short and wide to light the roadway close to the vehicle. (Illus- tration by P.DuPre/AutoWord) the prices coming way down, making them competitive against HIDs. The key to the brightness and light output is the size and num- ber of crystals used, the makeup of the crystals, the design of the epoxy surrounding the crystal and the lens used to direct the light. LEDs are also a lot more reli- able than traditional automotive lighting options. According to the folks at Vision-X, expected life cycle of an LED automotive light is about 50,000 hours versus the approximately 400 hours of other comparable lights. This means, eff ectively, in most cases a LED automotive light is a lifetime purchase. For commercial use, this is a double bonus since the LED also uses only about 85-percent of the energy required to operate quartz halogen or HID systems, saving wear and tear on batteries and alternators. LENS DESIGN Really good lights of any type have to have lenses designed to focus the light into a fl ood, spot or, in this case, fog-pattern beam. A properly-designed fog-light delivers a wide and relatively short (not more than 150 feet or so) beam pattern that is aimed low to increase road visibility near the vehicle during slow speed inclement weather driving. It should also have a lens de- sign that cuts off light above the vertical mid-way point so there's no light refl ecting back into the driver's eyes. This eff ect, called backscatter, is caused when up-angled light beams refl ect off the moisture droplets in the fog (or from the snow, misty rain or dust), which is why a vehicle's high-beams are totally useless under such conditions. The low-angled fog light beams avoid this problem by aiming light downwards and improving near-vehicle visibility, but with enough light output to light the road 100 to 150 feet ahead. BEST COLOR A well-designed lens makes the diff erence between a fog light that actually does the job and an ornamental fog light that just looks cool. Lens color adds to that performance diff erence. White (clear) is the more com- mon lens, although amber and yellow lenses work better in rain, snow and fog. Stay away from blue spectrum lights (color temps above 6,500 degrees Kelvin), found in many HID lamps off erings, as the eye doesn't respond as well, espe- cially at a distance. As for power, a higher watt output produces a brighter, more penetrating beam. Run- of-the-mill bargain fog lights are typically rated 35 watts, while the better, higher-performance models can come with 100-watt output, or the equivalent in LED. When you drive your pickup for business and spend a lot of time on the road in bad weather conditions, look for fog lights with an output of 55 watts or higher. MOUNTING/ AIMING Fog lights work best mounted in, on or below the bumper (10 to 24 inches above the road surface) or anywhere below the center of the headlights, where their beam can cut just under that of the low-beam headlights. The lights should be posi- tioned closer together than the headlights (approximately 20 to 26 inches between them) and aimed so the cut-off line of the beam is about the middle of the low-beam headlights' pattern. The best way to aim the lights is to park the truck on a level sur- face 25 feet from a wall. Measure the distance between the center of the fog light and the ground. Place a horizontal mark on the wall at that height. Visual aim is made with the top of the fog light beam about 4 inches below the lamp center at 25 feet with the lamp facing straight forward. If you drive over a lot of nar- row, winding country roads, angle the passenger's-side light slightly to the right of the low- beam headlight's center so the fog light illuminates even more of the road side. Also make sure they are wired propickupmag.com PROPICKUP 49