As an auto electrician, I often get asked why LED mine lamps fail. Going back seven or eight years, the lamps were mainly halogen and HID. Failures then were very different to what they are now with LED but the lamps were a lot cheaper and so people threw them away without too much concern. Main issues then were flimsy housings, which rattled to pieces and bulbs, which were really bad at taking vibration.
Now, with LED in full flow, the lamps are tougher and last longer but there is still a surprising amount of failures in the field. So what the go?
Well, first off the environment is unlike any other. The heat, dust, water cannons, vibrations and other forms of abuse do take their toll on any appliance. LED lighting is, after all, just a package of electronics in an aluminium box so there is always possibilities of something going wrong. So let’s look at these causes individually:
Overheating of LED’s is one of the primary causes of failure. This typically happens when the lamps are running 24/7 with little or no airflow. Most premier manufacturers use a temperature control device on the pc board which ensures that maximums are not exceeded. However, cheaper modules don’t have this and will therefore fail a lot quicker.
Dust and Water
Everyone claims IP-rating to prove their worth against dust and water. IP67 is the most common but can go up to IP69 on mobile lamps. This is quite a bold claim but is soon put to the test when a hot lamp gets dowsed by a water cannon. If not built properly the lamps will either leak directly or allow the air inside to condensate. Either way this is not great for the electronics, which will fail shortly after. The solution is good engineering for the seals and waterproofing, along with a breather valve to allow the air to change pressure without condensing.
Being solid-state, most LEDs are OK with vibrations. However, constant shaking and rattling will eventually wear components down or cause them to break off the pc board. To counter this many manufacturers now use rubber mounts which absorb a significant amount of vibrations. This also helps the brackets last longer, which can only stand so much of rigid shaking.
One of the causes of overheating would be a coating of coal dust, oil, mud etc. on the housing and the lens. This external crust prevents the lamp from giving off its heat and can cause terminal damage. This is remedied by regular washing, provided the lamp is capable of standing up to the blast.
The one way to assess how serious the manufacturer is, is by checking the detail of the warranty. For a supplier accustomed to supplying the mining industry, these factors mentioned above should be ‘all in a days’ work’. However, if you generally supply the leisure industry your expectations of ‘robust’ may be very different.
So, in conclusion, make sure you do the research before installing the lamps. Not all LED lamps are created equal and if you choose one for its price only, you may find that it becomes a very expensive lamp indeed.
Do a trial for four-six weeks to assess whether the units are made for the job and check references on other sites using them. This quickly flags up any issues that the company may have forgotten to mention and prevents some embarrassing situations.