They use only small amounts of electricity, they can deliver light in different colours, they illuminate almost instantly, they have a long life (up to 50,000 hours) and they are shock resistant.
The advantages of LED (light-emitting diodes) lights compared to conventional filament bulbs are numerous. No surprise then to find that LEDs are increasingly being used to illuminate brake lights, indicators, reversing lights on commercial vehicles and agricultural and cargo trailers.
Over the years the brightness levels of LEDs has increased significantly – from the small red glow of the early bulbs used to indicate, say, that a radio was switched on, to lighting that can be used to illuminate the inside of an aeroplane.
Lighting for agricultural trailers has traditionally suffered from lighting failures caused by water ingress, faulty earths, frayed wires, bulb failure, cracked or broken housings and so on. So what LED systems are available?
Britax, whose products are available through Kramp UK and is well known for its vehicle lights, has recently introduced a range of LED lighting systems – and they include flashing amber beacons.
One of the main features of an LED is its ability to be switched on and off without reducing its operating life – unlike conventional bulbs. The LED’s one millisecond response time also allows fast bursts of flashing to be achieved, since there’s no bulb filament to warm up.
The new Britax beacons use this feature by programming them to give bursts of five rapid flashes, 70 times a minute.LED lights can also operate successfully in a wide temperature range – from -30C to 50C. There is evidence that the lights actually get brighter at lower temperatures.
However, LED lights do not produce any significant heat so, in snowy or frosty weather, there is no heat available to keep the lenses clear as often happens with conventional lighting. Airports that use these lights on their runways have to fit heating systems to keep them clear of snow and ice.
Britax has also introduced a range of LED rear combination lamps which typically comprise a stop light, tail light, direction indicator and a reversing light which uses a conventional bulb.
Though LED lights have a very low power requirement, their modest current draw can cause a problem with vehicle indicator monitoring systems. When a bulb with a tungsten filament is used, the current draw is typically 21W.
However, an LED draws just 1.8-2.5W, which may be too low to be detected by the vehicle’s electrical monitoring system, with the result that a bulb failure light can come on – even though all is well.
To overcome this problem, Britax has introduced what it calls a “smart load device”, which simulates the power consumption of a tungsten filament bulb so the monitoring system does not give incorrect readings.
The fitting of LED lights on agricultural trailers in the UK continues to increase and some manufacturers now offer them as standard while others have them as an option.
One of the first companies to adopt LED lighting as standard was Inverurie-based Stewart Trailers, which has been fitting them to its range of tipping trailers, dumper trailers, flat trailers and livestock transporters for several years.
The low power requirement of such lights has enabled them to be placed not only low down at the rear of a tipping grain trailer, but also higher up on the top of the rear door – a useful aid to other road users when the car immediately behind the trailer hides the indicators from the queue of cars behind.
Included in the lighting package are side lights and front marker lights.The latest trailer manufacturer to adopt LED lights is Richard Larrington which, like Stewart Trailers, now offers a full lighting package for its trailers – including the important tailboard lights. “We started fitting LEDs as standard two years ago and we haven’t had to change a light bulb since,” says Mr Larrington. “They seem to last for ever.”
He adds there is an increasing demand from growers to have good lighting both for safe operation on the road and when unloading in dimly lit stores or at night.”To put sufficient conventional lights on a trailer would draw down a lot of power from the tractor and connections would no doubt start to heat up and fail,” he says.
“With LED lights there are no problems at all and they are easier to fit.”There is a cost though. LED lights are more expensive than filament bulbs – Richard Larrington charges an extra £750 for them, but he says customers agree that their reliability is worth the extra money.