How To Choose And Buy The Right Power Supply For My LED Strip Lights

How to Choose and Buy the Right Power Supply for My LED Strip Lights

Jason Chen
8 March, 2025

Why do LED strips use a constant voltage power supply?

Most household and decorative LED strips (such as 12V/24V/5V) are driven by constant voltage power because of their simple installation, low cost, and easy-to-match controllers (such as RGB dimming). Recently, the LED strip light “net red player” in the home improvement industry, from the living room to the balcony, can be seen! To make the LED light strip stable light, the LED power supply needs to provide a stable voltage because the LED is more sensitive to voltage fluctuations. If the voltage is unstable, it may lead to uneven brightness of the LED strip light and even shorten the service life.

The use of a constant voltage power supply for the LED strip is the core to ensure safe and stable operation. Constant voltage power supply can provide accurate and stable output voltage to avoid overload damage, uneven brightness, or stuttering problems caused by voltage fluctuations. The use of a high-quality constant voltage power supply can improve the lighting effect and achieve energy savings and consumption reduction, which is an important guarantee for the reliability of the LED strip light system.

● Standardized voltage: The common 12V/24V constant voltage power supply is highly matched with the specifications of the strip, and the user can directly purchase the power supply of the corresponding voltage without complicated calculation.

● Universal installation: the constant voltage power supply directly matches the lamp with rated voltage, can work after connection, and is suitable for DIY installation.

● Adaptive intelligence: The constant voltage lamp can be matched with a PWM dimmer or intelligent controller to achieve brightness and color adjustment to meet the needs of smart homes.

● Group power supply: The problem of voltage drop can be reduced by reasonable segmentation (such as connecting the power supply every 5 meters) or by choosing a higher voltage (such as 24V).

What is a constant voltage LED power supply?

A voltage power supply is a device that can automatically maintain the output voltage stability when the load changes. A constant voltage LED power supply is a type of power source that provides a stable, fixed output voltage, typically 12V or 24V DC, to LED lighting systems. It ensures consistent voltage regardless of load variations, making it ideal for LEDs connected in parallel. This type of supply is commonly used in applications like LED strips, signage, and decorative lighting, where maintaining uniform brightness is crucial. It is simple to install and cost-effective but requires proper voltage matching to avoid damage to the LEDs.

mean well constant voltage LED power supply

Where is the constant voltage power supply generally used?

Constant voltage power supply is widely used in the need for stable voltage occasions, such as electronic equipment chargers (mobile phones, computers), LED lighting systems (to ensure brightness stability), industrial control equipment (sensors, PLC modules), communication base stations, medical instruments (monitors, testing equipment), and laboratory precision instruments.

The application of constant voltage power supply in LED lighting is very common, especially in the common low-voltage strip; the use of constant voltage power supply reaches more than 90%, so to correctly install the strip, we must fully understand some knowledge of constant voltage power supply. Below I try to use a simple way to take you together to understand the constant voltage power supply in LED lighting, some of the main applications of common sense; I hope to help you.

How to choose the right constant voltage power supply?

Users may be considering the power supply for their own LED strip light, but they do not know which is more appropriate. Maybe he has a constant voltage power supply on hand or heard that the constant voltage power supply is more commonly used and wants to confirm whether it matches the LED strip light on his hand. In addition, he may be worried about whether the use of constant voltage power will have problems, such as whether it will burn out the strip or affect the life. In order to choose a good constant voltage power supply, we should consider from the following aspects.

Output voltage

First, determine the use voltage of the strip: the constant voltage power supply needs to match the voltage of the strip (such as 12V/24V). Observe the label of the strip or the printing on the strip, generally marked with the voltage value, and then select the power supply with the same voltage value according to the marked voltage value. As shown below, the strip is DC12V, and the selected power supply also needs to be a constant voltage DC12V power supply.

Voltage matching of LED strip to power supply

Input voltage

Voltage standards are different in different countries. For example, the United States is 120V, most of Europe is 230V, the United Kingdom is 230V, Japan is 100V, Australia is 230V, and so on. At the same time, it is also necessary to consider the different shapes of plugs, such as American standards, British standards, European standards, Australian standards, etc.

Most national voltage references：

Country	Voltage	Frequency
CHINA	220V	50HZ
JAPAN	100V	50/60HZ
KOREA	100V	60HZ
HONG KONG	200V	50HZ
THAILAND	220V	50HZ
INDONESIA	220V	50HZ
CANADA	120V	60HZ
ARGENTINA	220V	50HZ
MEXICO	120V	60HZ
U.S.A.	120V	60HZ
GUAM	110V	60HZ
ITALY	220V	50HZ
GERMANY	220V	50HZ
ENGLAND	240V	50HZ
FRANCE	127/220V	50HZ
GREECE	220V	50HZ
SWEDEN	120/127/220V	50HZ
NETHERLANDS	220V	50HZ
NORWAY	230V	50HZ
DENMARK	220V	50HZ
SWITZERLAND	220V	50HZ
FINLAND	230V	50HZ
BELGIUM	220V	50/60HZ
SPAIN	127/220V	50HZ
AUSTRIA	220V	50HZ

When selecting the input voltage of the constant voltage power supply, it is necessary to ensure that the input voltage matches the local power grid and to take into account the problem of voltage fluctuations; the grid voltage is not absolutely stable; there may be fluctuations of ±10%. For example, in the nominal 220V area, the actual voltage may vary between 198V and 242V. Therefore, the selected power input range needs to cover these fluctuations; otherwise, the power supply may not work properly or be damaged.

Rated power

How does the strip’s use match the power of the power supply? For example, we bought Philip DC24V, 5 meters/roll of the strip; the label marked 0.5 meters of power is 13W, 1 meter of power is 26W, and the total power of 5 meters of LED light belt is 26X5=130W. Then we need to match the power of 130W, but we need to reserve 20% of the total power of the lamp to ensure that the rated power of the power supply is enough. Finally, we can choose the constant voltage power supply with 150W Meanwell and DC24V: LRS-150W-24.

It is worth noting that if it is a remote installation, if the length of the strip is more than 10 meters (24V) or 5 meters (12V), it is necessary to supply power in segments or use thicker wires to avoid insufficient power supply.

Power factor

The level of PF value does not affect the use; in the case of conditions, try to choose the power supply with a high PF value. Of course, if you have cost concerns, you can also choose a power supply with a low PF value, and the price may be slightly lower.

The PF requirements may be determined by the energy efficiency standard of the external power supply (e.g., DoE Level VI), which usually requires PF ≥ 0.9. Users are advised to refer to the latest Energy STAR official documents or consult a certification body to ensure that the requirements are met.

Efficiency

The higher the efficiency of the power supply, the better; the less power lost by the higher efficiency, and the more energy-saving it is. For example, the figure below is MEAN WELL’s 100W power supply; its efficiency is 92%, and then its power loss is 8%. The power of each power supply will be slightly different; in the case of the same price, you can try to choose a high-efficiency brand power supply.

Certification

Different countries have different safety certifications, such as CCC in China, CE in the EU, UL in the United States, and so on.

CCC certification: mandatory for sales in China;

CE certification: essential for EU market access;

UL certification: North American market recommendation (optional but improved reliability);

PSE certification: Japan market mandatory certification.

Choosing a power source that meets local certification ensures safety and legality. Consider the efficiency and safety of the power supply.

Dimming

There are three common dimming methods for constant voltage power supplies:

1) PWM dimming, by adjusting the pulse width control brightness;

2) Analog dimming, changing the output voltage or current to achieve dimming, like 0-10V dimming;

3) Resistance dimming, using variable resistance to adjust the load power. Suitable for LED drivers and other scenarios.

IP level

The waterproof level of a constant voltage power supply is divided according to the international protection level IP code, which is usually 9 levels from IPX0 to IPX8, and the higher the number, the stronger the water resistance, such as IP67 to prevent short-term water immersion, and IP68 can be long-term diving. The specific grade is based on the comprehensive evaluation of dustproof and waterproof performance.

Each LED power supply is marked with an IP rating. Users can choose the appropriate waterproof standard power supply according to the environme.

FAQ

Can the American standard power supply be used in European countries?

Depending on the input voltage marked on the power supply, the power supply voltage of the United States is generally 100-277V, while most countries in Europe are 220-240 volts. In this voltage range, the United States can be used in Europe. On the contrary, can the power supply of European regulations be used in the United States? The answer is no; after all, the power supply in some parts of North America is 277V, and plugging it in directly will cause the power supply to burn out directly.

In addition, it should be noted that the manufacturing cost of a 100-277V wide voltage power supply will be higher than that of a 220-240V, and the cost of a wide voltage power supply is about 15-20% higher than that of a single voltage type. If you use the American standard power supply in European countries, this will lead to an increase in the cost of use.

The rated power of the constant voltage power supply is larger than the power of the LED strip; can the power supply be used?

The answer is yes, the general power supply with a 20%-30% margin (such as a lamp with a 40W and 50W power supply) is safer. In this way, the power supply can avoid long-term full-load operation, reduce heat, extend service life, and reserve space for subsequent expansion of the strip.

If the output voltage of the power supply is consistent with the rated voltage of the lamp strip (such as 12V), even if the power supply is larger, the lamp strip will only draw current according to its own needs and will not be overloaded. The power rating of a power supply represents its maximum power supply capacity, not a mandatory output value. However, if the power of the power supply is too much larger than the power of the LED strip, for example, more than 2 times. It will feel a little “overused,” and the utilization efficiency of the power supply will become low, indirectly increasing the cost and also causing the waste of energy. So the power supply is not the bigger, the better.

The power of the constant voltage power supply is smaller than the power of the LED strip. What will happen?

This situation needs to be avoided!

When the power of the constant voltage power supply is less than the power of the connected strip, the following situations may occur:

1). Low brightness or flicker—the strip may not reach normal brightness, and there is a significant dimming. If the power supply is severely insufficient, the strip may blink or even fail to start.
2). Power overload—The power supply will be in an overload state for a long time, resulting in increased heat, which may trigger overload protection (automatic power off). Continuous overload may damage the internal components of the power supply and shorten the service life.
3). Safety hazard—Overheating of the power supply may lead to aging of the line, melting of the insulation layer, and short circuit or fire risk in extreme cases.

There is a small part of the LED strip that is not bright. Is this a power problem or an LED strip problem?

Some LED strips usually fail over time during use, rather than all at once. If you notice that a small section of a light line is not bright or slowly dimming, your LED light may be broken. These emitters operate in series parallel circuits throughout the board. This means that if one transmitter is damaged, the rest will still light up.

This situation is not a problem with the power supply, but the LED strip is damaged. Maintenance is usually to replace this small section of the LED together or cut off the bad section and then connect.

Can the constant current LED strip be connected to the constant voltage power supply?

The constant current strip cannot be directly connected to the constant voltage power supply.

If the strip is designed with constant current, you cannot use constant voltage; otherwise, there may be problems.

Assume that the lamp strip is designed to operate at a constant current value, such as 350 mA, and the voltage of the constant voltage supply is fixed. At this time, the voltage requirement of the lamp strip may be higher or lower than the supply voltage.

For example, if the strip needs 18V at 350mA, and the power supply is 12V constant voltage, the current may not reach 350mA, resulting in insufficient brightness of the strip or not bright at all. On the other hand, if the strip only needs 9V at 350mA, and the 12V power supply is connected, the current may exceed the design value, causing the LED to overcurrent, heat, and even burn.

Constant current lamp → must be equipped with a constant current power supply.
Constant voltage lamp → Directly connected to constant voltage power supply.

If you are not sure about the lamp type, check the product label or consult the manufacturer to avoid damage to the device.

Conclusion

Signlite Opto-electronics is a leading enterprise in the field of LED strip light manufacturing in China, has been focusing on the development and production of LED flexible lighting technology since its establishment in 2013. With a self-developed high-precision patch process and optical optimization technology, the company has created a full range of light strip products with high color rendering and low light decay characteristics, covering interior decoration, commercial lighting, building lighting, and other fields of application. Exported to Europe, America, Southeast Asia, and other more than 10 countries and regions.

If you have technical problems with the power supply and LED strip light, please contact Signlite. We will be happy to serve you and welcome wholesalers, traders, agents, and our bulk purchases.

Signage & LED Strip Lighting Factory Since 2011