That one little side marker with its five amber LED diodes certainly changed things for the better. Grote is proud of the revolution in lighting performance we created in 1989.
LEDs have firmly cemented their value in every segment of the heavy duty and vocational markets.
The reasons are obvious to anyone who can read an expense report.
The list of the reasons why is a long one:
• Much longer life means far fewer maintenance interruptions to maximize fleet uptime
• Robust, solid state, potted circuitry provides corrosion
and vibration protection
• More energy efficient than incandescent and
most halogen lamps
• Operates much cooler
• No mercury
• No UV in beams
• Directed light for increased efficiency
LED Advantages over Incandescent Lighting
LEDs offer many distinct advantages over incandescent lighting in the trucking industry.
One of the most significant advantages between LEDs over incandescents is their superior aging characteristics and failure modes. As an incandescent bulb ages, material from the filament slowly evaporates and collects on the walls of the bulb. This darkens the bulb and lowers its light output. Eventually, enough material evaporates from the filament that it breaks and the bulb goes out.
LEDs, on the other hand, gradually decrease in output as they age, but they do so at a much slower rate than regular incandescent bulbs. Because of this extremely long life, it is impractical to define the end of life of an LED as the total cessation of light output. One commonly accepted practice is to define the end of an LED’s life as the moment when the light output drops to 70% of its initial value. Perhaps because we define LED life in terms of lumen maintenance, we tend to focus on the dimming of LEDs over time, while forgetting that incandescent bulbs do the same thing.
LEDs offer many advantages over incandescent lamps in terms of safety and economy. LEDs illuminate 200 milliseconds (ms) faster than incandescent bulbs. An incandescent bulb filament must heat up to achieve maximum brightness; this takes 100 to 300 ms. Further, LED lamps don’t exhibit a high in-rush current which might further delay the turn-on time. This faster turn-on time provides a safety benefit to the driver of the following vehicle. For a truck, this means a quicker braking distance response time for the vehicle following which can amount to more than a full car length of extra stopping distance at 65 mph. This instant-on time is not affected by low voltage regulation in a truck’s electrical system.
Besides their generally slower turn-on times, incandescent bulbs have the further disadvantage that their turn-on times are further increased when they are operating at lower voltages. This especially can be a problem due to the voltage drop in the wiring harness. A study by NHTSA of 546 large trucks showed that some trucks have such large voltage drops in the wiring that the voltage across the signal lamp is reduced to the range of 5.5 to 8.8 volts. By comparison, the turn-on time of LED lamps is relatively insensitive to low voltage.
LED Shock Resistance
Vibration and shock are conditions constantly introduced by the environment in which the product must function. Vibrations and shock can destroy or badly damage a device to the point that it must be replaced because it no longer will perform at the level intended. Products (i.e. lamps and safety equipment) that are required to comply with FMVSS-108 should be tested according to the vibration test as described in SAE J575e using the vibration test machine.
With filament based lamps such as incandescent, vibration and shock to the device can compromise the filament, the small wire suspended between two posts that glows to produce light when enough energy is applied to it. When vibration occurs or a shock is strong enough, the filament will start to swing between the two posts and will eventually break. LEDs are robust, stationary, and potted to resist shock and virtually eliminate failure due to vibration.
LED lamps are the most cost effective in several markets when lighting maintenance costs are taken into account over the life of the lamp.
Check for yourself how LEDs offer advantages over the use of incandescent with our ROI Caculator. This measures the true time cost of a lamp.
LEDs and Fuel Savings
In a vehicle, every watt of power must be generated and supplied by the engine. Even electrical components, which are connected to the battery, eventually receive their power from the engine running on the fuel tank. Even small electrical loads eventually add up to gallons of diesel fuel.
It is important to remember that lower amp draw helps to extend the life of the battery and charging system. The following calculations provide the logic and rationale for deriving the fuel savings that a vehicle would realize by switching from incandescent to LED lamps.
Looking first at the tail function, let us assume that for one year each light is operated for 4 hours per day for 240 days per year. This would result in 960 hours of operation per year. This number is assumed since most of the lights manufactured by Grote are for the heavy truck market.
Each LED Stop/Tail/Turn (STT) in the tail/park mode typically takes 0.04 Amps. The corresponding STT incandescent lamp takes 0.48 Amps. The current savings is 0.44 Amps. At 12.8 Volts (the industry standard for lamp design voltage for vehicles), the power savings is (0.44 Amps) x (12.8 Volts) = 5.6 Watts.
Operating at this savings for one STT for 1 year (960 hrs x 5.6 watts) results in an energy savings of 5.4 KW-hrs/year. Multiply that over 1.5 million Grote STT lamps produced in one year, and the energy savings is 8100 MW-hrs.
Incandescent lamps can have over 12 to 1 ration in power consumption over an LED lamp. An LED STT in tail mode has a 0.04 amp draw. An incandescent STT in tail mode has a 0.48 amp draw.
Looking at the brake and turn functions, these lamps function 5% to 24% of the time, depending upon the amount of city or highway driving. This calculation will use a 5% function time, since the primary market is the truck-trailer market. Each LED STT typically takes 0.24 Amps in the brake/turn mode. The corresponding STT incandescent takes 2.1 Amps. The current savings is 1.86 Amps. At 12.8 Volts (the industry standard for lamp design voltage for vehicles), the power savings is (1.86 Amps) x (12.8 Volts) = 23.8 Watts.
Operating at this savings for the brake/turn function for one STT for one year results in an energy savings of 1.1 KW-hrs/year. Multiply that over 1.5 million Grote STT lamps produced in one year, and the energy savings is 1,650 MW-hrs.
An LED STT in turn or brake mode has a 0.24 amp draw. An incandescent STT in turn or brake mode has a 2.1 amp draw.
There is a wide range of marker lamps. The current requirements for LED marker lamps range from 0.06 to 0.1 Amps. Incandescent marker lamps range from 0.27 to 0.66 Amps. For the sake of this calculation, the difference between the highest rated LED lamp and the lowest rated incandescent lamp will be used (0.27 Amps – 0.10 Amps = 0.17 Amps). This would provide the minimum energy savings for the conversion of incandescent to LED marker lamps.
Following the same sequence of calculations as the STT lamps, one LED marker lamp would save at least 2.2 Watts. Using the one year of operation provides an energy savings of 2 KW-hours/year. Multiplied by 1.2 million marker lamps per year, the savings comes to 2500 MW-hrs/year.
Incandescent lamps can have over 12 to 1 ration in power consumption over an LED lamp. An LED marker lamp has an amperage draw range from 0.06 to 0.1 amps.
An incandescent marker has an amperage draw range from 0.27 to 0.66 amps
Typical Trailer Configuration
Below is a typical configuration on a standard dry-van trailer. This chart shows the lamp type, number of lamps required for the function, and the total amperage of that series of lamp for both incandescent and LEDs.
If you haven’t re-equipped your fleet – or your rig – better get some Grote CSA Lighting Emergency Kits. You’ll need them.