We often hear in the press and trade magazines about the (supposed) benefits of LED lighting. So the, what about the down-sides? Is it really that amazing, and if so, why hasn’t every sports field in the country changed over yet? Why are there new fields being made that still have the dreaded old technology metal halides?
Like all things in life you get good and bad products, and when choosing LED lighting for your sports club, or your latest design, there are a number of things to be aware of. If you’ve ever been involved in an LED upgrade that’s gone wrong, you’ll know what I’m talking about.
Weight and sail area
Most poles have been designed for metal halide fittings. Whilst these are quite large, they are relatively light for their size. Due to the way these bulbs work, all the heat comes out the front so there is no need for heat sinking. By contrast LED’s generate heat out the back and therefore need a critical mass of aluminium to remove the heat from the LED’s and prevent them overheating. This mass depends on the efficiency of the lamp and can tend to be very heavy compared to the metal halide. Before swapping out make sure that the poles can cope with the weight, unless you have selected a lamp that can replace metal halide one for one.
Most LED’s have been designed with an optic that produces a round halo of light, compared with an asymmetric pattern found with most metal halides. This can be very inefficient and you need to make sure that your existing light levels can be achieved with a similar number of modules (to prevent pole overload) and current draw (to prevent using more electricity). Ideally find a lamp with an asymmetric pattern similar to the modules you currently have. In this way you can be more assured of a good one-for-one switch over.
Angle of fitment
Most metal halides are designed to be mounted flat, or horizontal. This ensures that there is a reduced chance of players being affected by the glare from the lamp as the lamp is ‘throwing’ the light forward. With many LED’s the optic is designed such that the light is emitted directly out the front of the lamp. This requires the lamp to be at a 20-45° angle, potentially interfering with the players’ sight during play, dazzling them if they look near the light from the wrong direction. Ensure that the fittings are designed to be mounted horizontally (or a maximum incline of 10°) or make sure that the pole positions are placed such that it won’t affect play. This, along with the beam pattern can also affect the amount of spill-light which can be annoying for neighbours. Check this carefully when you have the lighting plan done.
As mentioned above it should not be assumed that LED will automatically be more energy efficient. In many systems, more watts of LED power are required to match the light output achieved by a 2kW metal halide. This needs to be checked once the lighting layout has been confirmed and required lux levels achieved. Add up the amperage required as an upgrade to your power supply later is an expensive option.
Typically LED lighting is expected to last 50000 hours. This is somewhat of an industry expectation but many never do. One of the primary issues is the drivers or power supply. This is the ‘brains’ of an AC powered system and the quality of the driver is often the quality of the system. Check the brand and factory guarantee of driver as this is likely to be where problems occur.
LED’s are more sensitive to moisture than the rugged old metal halides. The manufacturers will generally be offering a warranty of some description but the lamps should have a minimum of IP65 for water and dust protection.
Colour Rendering Index (CRI)
Metal Halide fittings naturally have a high CRI and so this high definition has largely been taken for granted. With LED’s we have to choose what CRI is needed for the application and will range from 60 to 90+. If the lighting is purely for training purposes, then almost anything will work. However, for televised games and large capacity crowds, it is important to have a CRI of 90+ otherwise a lot of the detail will be lost through poor colour definition.
So, after knowing all these potential issues with LED is it really worth it? The answer is definitely ‘Yes’ but research into which fittings you get is very important. In short, it’s easier to get it wrong than to get it right. Look into these aspects and once you’ve ticked them all off with confidence you’ll have a lighting system that will provide exceptional performance for many years to come.