In Focus: Lighting

In the early 1990s, the top three maintenance costs were lighting, tires and brakes, with lighting ranked No. 1 in frequency of repair, says Brad Van Riper, senior vice president and chief technology officer of Truck-Lite. The company has been producing truck lighting based on light-emitting diode (LED) technology since 1991. “The core benefits that attracted us to the idea of making them are still what attract buyers,” Van Riper says.

Early adopters of LEDs were those who reviewed their maintenance costs, he says. “Their usage of LEDs has meant that lighting dropped off the top 10 list of maintenance areas in frequency and cost. A small investment up front yields years of savings and dependability.”

Travis Hopkey, director of marketing at Phillips Industries, says there is one vocation where LEDs not only save maintenance, but also provide a critical improvement in performance: refrigerated food hauling. In recent years, many reefer fleets have switched to fluorescent lighting to reduce the power consumed in lighting the trailer.

“Fluorescents were not doing the job,” Hopkey says. “Our LED product was designed after listening to the fleets and the drivers’ unions.” The problem wasn’t just the cost of replacing the bulbs in dome lamps at $10 each, but poor lighting, including delivering the wrong package because the driver couldn’t read the label, Hopkey says. “Ballasts take time to fire up under cold conditions,” he says. “And a repair could take a half-hour by the time the technician found the right bulb.”

Page Large, national fleet sales manager at Grote Industries, cites three key advantages to LEDs: amperage draw, safety – instant on or off lighting – and extended life. As far as the last item goes, LEDs in all colors but white are rated at 100,000 hours. “Turn one on and leave it on, and it would be 11 years before it would fail,” Large says. “And flashing on and off does not shorten life the way the line surge that occurs with a filament does.” With no filament, vibration does not damage the light, Large says. “It’s a great product for any application where components are often subjected to vibration damage.”

Grote also is finding a market in reefer trailer dome lamps. “There are a lot of deliveries on many of the different routes,” Large says. “Because they give better light, they cut down on worker’s compensation claims.”

Reduced current draw is another advantage, Large says. For example, if a fleet is looking for an alternative idling solution other than adding APUs, it might accomplish its goals “without adding batteries or upgrading the alternator,” he says. “Bottom line, when you look at the actual return on investment, it opens eyes.”

How they work
An incandescent lamp is essentially a piece of wire in a bottle. Every incandescent lamp contains a tungsten filament; when current flows through the filament, it encounters resistance, and the wire heats and glows brightly. Over time, the tungsten evaporates, and the filament wire burns out.

An LED is a solid-state electronic component. When current flows through the semiconductor compounds, light is emitted. “Because there is no evaporation of components and it is solid state, life is significantly longer,” says Mike Phillips, A.L. Lightech’s national sales manager. Where LEDs may live for 100,000 hours, incandescents can fail at between 200 and 15,000 hours, “depending upon the type of bulb and the environment it is exposed to,” he says.

How they save
An LED’s current draw is lower because it produces the actual color that’s emitted, Large says. “If you take the lens off, the color of the light is the same,” he says, “This saves power because the lens on a colored incandescent light actually is filtering out all but the red or yellow frequencies.”

Reduced current draw can provide savings in a number of ways. Most LEDs draw about 25 percent of the power of an equivalent incandescent, and Phillips says A.L. Lightech’s may draw as little as 16 percent. A 160-amp alternator at full power takes at least 2.5 hp to drive, which means running the alternator may, at times, consume 1 percent of the fuel in a typical truck under highway cruise conditions.

Reduced power draw also means reduced voltage drop in a long trailer. The voltage at the rear of a 53-foot trailer is often only 9 to 10 volts. “Using LEDs leaves more power for the ABS,” Van Riper says.

Phillips’ Permalite LED trailer dome lamps actually regulate the voltage going to the LED itself, so whether supply voltage is 9 or 30, the light output is the same, Hopkey says. Phillips also offers a product called Permalogic, available on Utility and Great Dane trailers; it’s an intelligent microchip that turns the trailer interior lights off when the driver touches the brakes to give the ABS full power, in case the driver has forgotten
to turn the lights off. Permalogic also automatically switches off the interior lights after one hour, Hopkey says.

As with so many items fleets may end up purchasing, “Every LED is not an LED,” Hopkey says. “You can buy newer designs of diodes that draw less current so they last, or inexpensive ones that run hotter. Watch for high stress.” Van Riper, who agrees with Hopkey, referenced Haitz’s law, which predicts that LED output in lumens (visible light) per watt will double every five years, thanks to research and development. “Converting a high percentage of the power into light means less heat, and heat is the enemy,” Van Riper says.

Van Riper also pointed out the safety advantage of a brake lamp that comes to full intensity immediately, as compared to an incandescent that takes almost 1/5 of a second. “If you’re following a vehicle with LEDs at 60 miles per hour or 88 feet a second, that gives you an extra 1/5 of a second, during which your vehicle will travel 18 feet,” he says. A.L. Lightech’s Phillips mentioned that at 65 mph, the 18 feet could expand to as much as 24 feet.

Quality is important, and both Large and A.L. Lightech’s Phillips say the LED’s circuit board should be potted. Potting is a gel-like substance that cures and hardens, encapsulating the circuitry and providing added protection, Large says. Also, a wiring harness should be well integrated with the LEDs themselves and incorporate high-quality connectors. Vendors also should guarantee service to correct any problems, and to check continually for compliance with changing Department of Transportation regulations.

Trailers are easier to retrofit than tractors because lights are more standardized, so fleets should evaluate whether or not retrofitting might be worthwhile based on the age of a trailer and its trade cycle. Payback can occur in three years, and occasionally a little sooner, says Truck-Lite’s Van Riper, who recommends that companies make sure they are keeping the trailer for more than those three years. Large agrees: “If you have trailers five years old and trade them at seven years, it probably does not make sense to convert to LEDs.”

And as in every other situation in heavy-duty purchasing, find out whether or not your supplier is committed to serving you by solving your problems. “We spend our share of time at the fleets,” Hopkey says. Whoever supplies your LED lighting should do likewise.