Guide: How To Choose the Right LED Power Supply

Why do you need an LED power supply?

Because most of our LED strips work at low voltage 12Vdc or 24Vdc, We can’t directly connect the LED strip to the mains 110Vac or 220Vac, which will damage the LED strip. Therefore, we need an LED power supply, also called an LED transformer, to convert the commercial power into the corresponding voltage required by the LED strip, 12Vdc or 24Vdc.

Factors you need to consider

Finding the correct LED power supply for LED strips is not an easy task. There are many factors to consider when picking the most suitable LED power supply, and you need to know some basic LED power supply knowledge.

Constant voltage or constant current LED power supply?

What is a constant voltage LED power supply?

Constant voltage LED drivers typically have a fixed voltage rating of 5 V, 12 V, 24 V, or some other voltage rating with a range of current or maximum current.

All our LED strips must be used with a constant voltage power supply.

What is a constant current LED power supply?

Constant current LED drivers will have similar ratings but be given a fixed amp (A) or milliamp (mA) value with a range of voltages or maximum voltage.

Constant current power supplies generally cannot be used with LED strips. Because the current of the constant current power supply is fixed, the current will change after the LED strip is cut or connected.

Wattage

You need to find out how many watts the LED light will consume. If you wish to run more than one light with one power supply, you must add the wattages to find the total wattage used. Ensure you have a big enough power supply by giving yourself a 20% buffer of the total wattage calculated from the LEDs. This can quickly be done by multiplying the total wattage by 1.2 and then finding a power supply rated for that wattage.

For example, if you have two rolls of LED strips, each roll is 5 meters, and the power is 14.4W/m, then the total power is 14.4*5*2=144W.

Then the minimum wattage of the power supply you need is 144*1.2=172.8W.

Voltage

You need to ensure that your LED power supply’s input and output voltage are correct.

Input voltage

The input voltage is related to which country the power supply is used.

The mains voltage in Australia is 240V.

But some LED power supplies are full voltage range input, which means this power supply can be used in any country worldwide.

Output voltage

The output voltage needs to be the same as your LED strip voltage.

If the output voltage exceeds the LED strip power supply, it will damage the LED strip and may cause a fire.

Dimmable

All of our LED strips are PWM dimmable, and if you need to adjust their brightness, you must ensure your power supply has the dimming capability. The data sheet for the power supply will state whether it can be dimmed and what type of dimming control is used.

Common dimming methods are as follows:

1. 0/1-10V Dimming
2. TRIAC Dimming
3. DALI Dimming
4. DMX512 Dimming

Temperature and waterproof

An essential factor that cannot be ignored when choosing a power supply is the use area and use environment. The power supply operates most efficiently if used within its temperature parameters. Power supply specifications should include a safe operating temperature range. It’s best to work within this range and ensure you don’t plug it in where heat can build up and exceed the maximum operating temperature. It’s usually a bad idea to plug a power supply in a cubicle that doesn’t have a ventilation system. This will allow even the smallest heat source to build up over time, ultimately cooking power. So ensure the area isn’t too hot or too cold, and the heat doesn’t build up to damaging levels.

Each LED power supply is marked with an IP rating.

An IP rating, or Ingress Protection Rating, is a number assigned to an LED driver to indicate the level of protection it offers against solid foreign objects and liquids. The rating is typically represented by two numbers, the first showing the protection against solid objects and the second against liquids. For example, an IP68 rating means the equipment is completely protected against dust ingress and can be submerged in water up to 1.5 meters for up to 30 minutes.

If you need to use the LED power supply outdoors where it is exposed to rain, please select an LED power supply with an appropriate IP rating.

Efficiency

Another critical characteristic in choosing an LED driver is efficiency. Efficiency, expressed as a percentage, tells you how much input power the driver can use to power the LEDs. Typical efficiencies range from 80-85%, but UL Class 1 drivers that can operate more LEDs are typically more efficient.

Power factor

The power factor rating is the ratio of real power (Watts) used by the load compared to apparent power (Voltage x Current drawn) into the circuit: Power factor = Watts / (Volts x Amps). The power factor value is calculated by dividing real power and apparent value.

The range for power factor is between -1 and 1. The closer to 1 the power factor is, the more efficient the driver is.

Size

When choosing a power supply for your LED project, it’s essential to know where it needs to be installed. If you want to put it inside the product you are making, it has to be small enough to fit in the space provided. If it’s outside the app, there should be a way to mount it nearby. A wide variety of power supplies are available in different sizes and shapes to suit your needs.

Class I or II LED driver

Class I LED drivers have basic insulation and must include a protective ground connection to reduce the risk of electric shock. Their safety is achieved through the use of basic insulation. It also provides a means of connecting to a protective grounding conductor in the building and connecting these conductive parts to the earth if the basic insulation fails, which would otherwise generate a dangerous voltage.

Class II LED drivers not only rely on basic insulation to prevent electric shock but must also provide additional safety measures, such as double insulation or reinforced insulation. It does not depend on either the protective ground or the installation conditions.

Safety protection function

For safety reasons, LED power supplies should have protection features such as over-current, over-temperature, short-circuit, and open-circuit. These safety measures lead to a faulty power supply shutdown. These protection features are not mandatory. However, if you want to use it safely in case of problems, you should only install power supplies with these protection features.

UL listed certification

LED power supply with UL certification means better safety and better quality.

Also, some projects require the LED power supply to have UL certification.

How to connect LED strip lights to the power supply?

After choosing the right LED strip power supply, we connect the red and black wires of the LED strip to the corresponding terminals or leads of the power supply, respectively. Here we need to pay attention to the positive and negative terminals of the strip. They must correspond to the positive and negative poles of the power supply output. (The symbol + or +V indicates the red wire; the mark – or -V or COM indicates the black wire).

Can I connect many LED strips to the same LED power supply?

Yes, you can. But make sure that the wattage of the LED power supply is sufficient, and make sure that the LED strips are connected to the LED power supply in parallel to reduce the voltage drop.

How far can I install an LED tape from its LED power supply?

The further away your LED strip is from the power source, the more noticeable the voltage drop will be. If you’re using long cables from the power supply to the LED strips, make sure those cables are made of thick copper and use as large-gauge cables as possible to help minimize voltage loss.

Tips for installing LED power supply

LED drivers, like most electronics, are susceptible to moisture and temperature. You need to install the LED driver in a dry location with plenty of air and good ventilation to maintain its reliability. Proper mounting is critical for air circulation and heat transfer. This will ensure optimal performance and long life.

Leave your LED power supply some spare wattage

Make sure you do not consume the entire capacity of the power supply. Leave some room to use only 80% of your driver’s maximum power rating. Doing so ensures that it will not always run at full power and avoids premature heating.

Avoid overheating

Ensure that the LED power supply is installed in a ventilated environment. This is beneficial to the air to help the power supply to dissipate heat and ensure that the power supply works to a suitable ambient temperature.

Minimize the “on” time of the LED power supply

Install a switch at the mains input end of the LED power supply. When lighting is not required, disconnect the switch to ensure that the LED power supply is truly off.

Troubleshooting common LED power supply issues

Always ensure correct wiring

Before applying power, the wiring needs to be checked in detail. Incorrect wiring may cause permanent damage to the LED power supply and LED strip.

Make sure the voltage is correct

You must ensure the LED power supply’s input and output voltages are correct. Otherwise, the incorrect input voltage may damage the LED power supply. And the wrong output voltage will damage the LED strip.

Make sure that the LED power wattage is sufficient

When the LED power supply wattage is insufficient, the LED power supply may be damaged. Some LED power supplies with overload protection will automatically turn off and on. You may see the LED strip constantly turn on and off (flicking).

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