Using the correct power supply or transformers for your LED lighting is important if you want it to work safely and efficiently.
Whether you’re installing new LED lights, transitioning from traditional forms of lighting like halogens or retrofitting your current fixtures, you may be required to replace your old transformers with LED drivers (these drivers are special types of transformers designed specifically for LEDs).
Some LED bulbs work with mains 240V or AC (Alternating Current) electricity. While other LEDs run on 12V DC (Direct Current).
But whatever type you decide to run with, all LED bulbs will require a driver to function properly. Mains voltage LEDs have the driver built in to the bulb, whereas the 12V LED bulbs use an external driver (like halogen bulbs do).
LEDs Use Much Less Power Than Halogens – Which Can Cause Problems
Halogen bulbs need a lot more power than LEDs do. Much more, in fact.
Which means halogen transformers provide a lot more power than LED lights need. Sometimes, you have to replace the old transformer with an LED driver to control the voltage and stop it blowing the LED (especially if you get lots of power surges from thunderstorms, for example).
So how do you tell if you need to change the transformers?
One way is to look at your old halogen bulbs and see if they have pins or pegs to plug them into the power circuit. Basically, pins need a new transformer and pegs do not. But it’s generally a good idea to install an LED driver regardless.
This is because the higher voltage from the halogen transformer can damage the LED and actually result in lower light output. You see, LEDs require such little power that they never pull the minimum wattage that the old transformer is rated for. Which leads to lights that are dim or flicker or lights that don’t turn on at all.
What Makes LED Lighting So Much Better Than Other Lighting?
LED – or Light Emitting Diode – together with OLED (Organic Light Emitting Diode – like that used in high-end TVs) and PLED (Polymer Light Emitting Diode) are classified under a technology known as Solid State Lighting (SSL).
Instead of electrical filaments, gas or plasma, SSL devices emit light through electroluminescence. This is when an electric current passes through a semiconductor diode causing it to dissipate energy as heat and light.
Compared to compact fluorescent lights (CFLs), SSLs don’t contain dangerous substances or shatter when they’re dropped. And they don’t emit ultraviolet radiation, which is notorious for bleaching artwork, flooring and furniture.
LED technology is fast replacing conventional incandescent and fluorescent lighting due to its low energy consumption and longer operational life.
Originally, LEDs were used as indicator lights in clocks, radio transmitters, christmas tree decorations and television sets. They then found their way into traffic lights, electronic billboards and car headlamps.
You will also find LED technology in flashlights, cameras, smartphone and TV backlighting and accent lighting. People continue to find interesting ways to use LED lights in car sunroofs, bionic contact lenses, motorcycle light strips and even glow in the dark eyelashes.
Types of LED Transformers or Drivers
Constant Voltage Transformers
Constant voltage transformers power products that call for a constant direct current voltage. They run LEDs that have a fixed voltage rating of 24V, 12V, 5V or a higher voltage rating with a maximum current.
Their flexibility makes them ideal for powering multiple parallel LEDs such as LED strips (the voltage output of the strips must meet the requirement for the whole LED string).
You can add more LEDs in a parallel system until you arrive at the maximum current of the transformer. There will only be one negative outcome – reduced brightness but the system will work flawlessly.
Constant voltage transformers are cheaper and popular with installation engineers and they are found in LEDs used in:
- LED strips
- Stage lights
- Street lights
- Outdoor lights
Constant Current Transformers
Constant current transformers are used to supply power to LEDs that have a current limiting resistor and run on a designated current measured in amps (A) or milliamps (mA) with a maximum voltage. They vary the voltage along the circuit, allowing the current to remain constant throughout your LED system.
If a never ending current and limitless voltage were to power an LED, it would continue to consume more current until it finally gave out. In this way, it maintains consistent brightness across all your high power LEDs and avoids thermal runaway, a phenomenon where excess current results in increased temperature and premature burn outs.
Due to their efficiency and better control of LED applications, constant current LED transformers are popular with designers. They are usually used for individual bulbs. If you choose to use these transformers in a series, none of your LEDs will work if the circuit is broken.
Constant current transformers are found in LEDs used in:
- LED signs
- Retail shops
- LED downlights
Consider 6 Key Factors When Choosing an LED Transformer
LED transformers operate safely and efficiently within their set temperature parameters.
Avoid placing your LED transformer in a poorly ventilated area as this will lead to heat build-up and damage.
- Mean Time Before Failure
The life expectancy of a transformer depends on how well you run it on your LED applications. It will take thousands of hours for the transformer to flatline unless you disregard the recommended outputs when you’re running your LEDs.
Using the device correctly will prolong its lifespan and lower maintenance costs. According to LEDs Magazine, if the temperature of your LED transformer is properly controlled, it should produce more than 70% of its initial light output after 50,000 hours.
- Output Voltage
This is specified in volts and it’s crucial to match the value you observe to your LED’s voltage requirement. If you plan to use multiple LEDs, sum up the individual voltages and then get a transformer that matches the value.
- IP Rating
Determine how water or dust-resistant your LED transformer needs to be. Will it be prone to wetness, dust or solid objects after you install it?
An IP rating of 44 will protect it from objects that are thicker than 1mm and splashing water but not dust. An IP66 rated transformer will be protected from dust and water.
The IP rating is given as a number with the first digit representing protection against solid objects of different sizes while the second specifies the pressure of liquids such as water droplets.
- Output Current
Observe the current requirements on the transformer usually specified in amps or milliamps. It can be given in values such as 350 mA, 500 mA, 700 mA, 1050mA or in a range like 0 mA to 500 mA.
Match the amp rating to the one required for your LEDs. You might want to run your LED applications at a lower current to improve durability.
- Output Wattage
Ensure that the transformer has at least the same or higher value of watts as your LEDs for safety.
Your LED transformer will have a shorter life expectancy if the output is equal to the LED’s average power requirement. This is because the transformer is already running at maximum power.
If you intend to run more than one LED off of one transformer, find the total watts used by summing up the wattages. Next, take the total and add a 30% buffer to it then find a transformer rated for that wattage.
An electrician will charge at least 80 AUD per hour to change your transformer. Of course, you could do it yourself, but get it wrong and you could end up spending more in expesnive repairs or worse, hospital bills.
An expert on the other hand will maximise your LED lighting investment through proper wiring and set up. Get a few quotes and find a tradie who fits your budget.