12V and 24V Power Adapters

Major advantages of 12V DC and 24V DC power adapters

1. Small size and light weight. Power adapter is smaller than switching power supply, lighter in weight and more convenient to use.

2. Low power consumption and high efficiency. Modern switching power adapters have advanced circuit design, and utilize high frequency conversion technology. The power consumption of power adapters is low, and the power efficiency has improved to a very high level, up to 90%, making the operating temperature also low.

3. Easy to install. AC DC power adapters usually have a DC male connector. LED light strips, laptops, and game consoles come with a DC female plug that can be used right away when plugged in. While the installation of switching power supply requires a certain amount of expertise, and the wiring is more complicated.

4. High filtering efficiency. Due to the high operating frequency of the AC DC power adapter, the filtering efficiency is nearly 1000 times higher than that of the linear regulated power adapter. This type of filtration is very good for sensitive LED light strips, which makes the light strips work under a smoother current and extends the lifetime of the light strips.

5. Steady voltage output. A stable voltage output can still be achieved in the case where the input voltage fluctuates in relatively large range.

Because power adapter has so many advantages, it is widely used as the power source for LED strips, and is the best choice for small installation of LED strip lights.

The highest power for 12V AC DC power adapter is 100W, and the highest power for 24V power adapter is 120W. Their specific power ratings are as below:
12V - 2A(24W), 3A(36W), 4A(48W), 5A(60W), 6A(72W), 7A(84W), 8A(96W), 10A(120W).
24V - 1A(24W), 1.5A(36W), 2A(48W), 2.5A(60W), 3A(72W), 3.5A(84W), 4A(96W), 5A(120W).

Generally speaking, switching power supply has higher power. The power of switching power supplies can be 200W, 300W, to 1500W or even higher.

There are many brands and manufacturers for power adapters. Choosing to buy a good power adapter is very important to your light strip. It not only helps you enjoy the uninterrupted lighting effects, but also ensures the lifetime of your light strip.

How to choose a good quality AC DC power adapter?

Based on professional experience, consider the following factors when purchasing an adapter.

1. Check to see if it is UL listed.

It is very important to make sure you buy an AC DC adapter that is certified for safety and performance standards. A UL listed AC DC adapter is strongly recommended. UL certified power adapters have passed the power supply standards of Underwriter Laboratories(UL). They are assured for the electrical capacity of electrical components and the operation result of the adapter.

For example, a UL listed of 60W power adapter will provide a maximum output that is enough 60W. Many AC DC adapters on the market that are not UL listed do not provide enough output wattage as they claim. They use less quality components and lower performance.

Class 2 adapter

Many practitioners who work on luminaires and power supplies don't know what kind of power supply the Class 2 adapter is. Why do more and more customers need such power supplies now? We provide a brief introduction for everyone. After reading it, you will have a more comprehensive understanding.

Earlier, UL had a standard specifically for Class 2 power supplies. This standard is UL1310. To achieve the Class 2 standard, the UL1310 standard must be used for assessment. The most common understanding is that the power supply that meets the Class 2 standard has a safer power circuit. It poses lower risk to a fire initiation and provides acceptable protection from electrical shock.

According to the standard definition, Class 2 power supply requirements meet at least the following conditions:

• Isolated Output. The entire circuit is divided into primary (input) and secondary (output), and the primary and the secondary must meet electrical clearance and creepage distance requirements
• The maximum output parameter must not exceed the limit value (inherently and not inherently limited).

Class 2 output limit:

• DC output: < 60 VDC limited by overcurrent protection
• Output current: < 8 A

Later, the power supply standard UL8750 for LED lighting products included the Class 2 power standard into its own standard, which means that a power supply that meets the requirements of the standard UL8750 will also be deemed to have met the Class 2 standard. We have carefully selected for you many modes of power adapters and power supplies that have obtained UL1310 Class 2 certification.

We do recommend you use UL listed power adapters or LED power supplies for your LED strip lights. Pay close attention and check the UL number validity if needed.

Related Reading:
How To Choose the Right LED Power Supply?

2. Energy efficiency standard DOE VI.
A new direction of energy conservation is the US DOE VI standard. The US Department of Energy imposes stricter requirements on the energy efficiency rating of power supply products in terms of average energy efficiency and standby power consumption. The standard was raised from Level V to Level VI, with the average efficiency 88%, and the standby power consumption 0.1-0.21W.

The DOE Energy Efficiency VI standard also complies with the green trend of environmental protection and energy conservation, and has set a standard in terms of power supply to further meet the needs of both lower output and higher output power applications.

3. Enclosure casing.
You can tell an AC DC power adapter's quality from the outer casing. If the power adapter has a rough surface, not smooth, and a poor hand feeling, indicating that the power supply housing is poor.

4. AC power cord.
Check the AC power cord to see whether the surface of the cord is printed with UL certification. And the cord should not be too soft. Usually power adapter manufacturers don't produce AC power lines by themselves. Some manufacturers have UL certification for the power adapter, but in order to save costs, they choose AC power cord that does not have UL. Our power adapters are UL listed for both the adapter and the AC power cord.

5. Weight.
The more straightforward method is to examine the quality by feeling the weight. For AC DC power adapters of the same specification, such as 12V 3A, if one brand is noticeably heavier than another brand, generally indicating the lighter one is inferior in quality. Because the materials used for quality power supplies have a common weight. Large deviation from the common weight means the lack of sufficient material for internal parts, directly affecting the reliability of the product.

Difference between AC DC wall adapter and desktop power adapters

There are two types of power adapter: ac dc wall adapter and desktop power adapter. The wall adapter is also known as power plug adapter, which is simply a power adapter that can be directly plugged into the power socket on the wall. The desktop power adapter, also called desktop power supply, is usually placed on the desktop or left on the floor. The difference between wall adapter and desktop power adapter is that the desktop power adapter requires an AC power cable to connect to the mains power. In many application, both wall adapter and desktop power supply are plugged into the power strip for mains power.

Power adapters are widely used in LED strip lights, security products, communication products, small household appliances, and consumer electronics. Especially in portable consumer electronics and communication products, they are generally less than 10W. For example, smart phones and tablets generally use 5-10W power adapter. Computer peripherals, security products, and small household appliances generally use power adapters less than 36W, especially with the increasing awareness of energy conservation and environmental protection.

Generally, most power adapters less than 36W are made as wall adapters. Wall adapters do not require AC power cord, which saves cost and space. Unlike desktop power adapter, wall adapter does not need the countertop space to place it on. It is directly plugged in the wall socket or power strip. It is also safer because no AC power cord is put in use.

Only a few power adapters less than 36W are made as desktop type. This is generally due to the fact that the electric product to be powered is far from the power socket, or because the wall adapter is too bulky to be plugged into power strip or socket crowded with plugs. A power adapter larger than 36W is not suitable to be made as wall plug type. Because of the large size and weight, power adapters above 36W are usually made as desktop type.

How to choose the right AC DC power adapter for LED strips: 12V or 24V power adapter?

Step 1. choose the right voltage.

LED light strips typically operate on 12V 24V DC power. Therefore, small strip light projects often need to choose 12V or 24V power adapter.

If you are a newcomer to LED strip, it is recommended that you use an easy-to-install 12V LED strip with a 12V power adapter. Since there are many other devices in daily life that use the 12V adapter, it is very generic and easier to find on the market.

If your installation requires a 24V LED strip, you will need to choose a 24V adapter.

Related Reading:
All you need to know before buying LED strip light.

Are the 24V 1A and 12V 2A LED strip light adapters interchangeable?
No. The voltage of the power adapter must match the voltage of the light strip. If the 12V power adapter is used to drive the 24V LED strip, the voltage is not enough to drive the lights and the lights won't turn on. If the 12V light strip is driven by the 24V adapter, then the voltage is too high. The LEDs will be burned out and the light strip will be destroyed.

To replace an LED strip light adapter, the same voltage should be choosen. The current is equal to or greater than that of the original adapter, and cannot be less than the original adapter current.

Comparison of 12V wall adapter and desktop power adapter
Wall adapter is big in the input side, so it is less usable on a power strip. In addition, the outlet blades of wall adapter are usually oriented in a degree that the wall adapter occupies several plug holes on the power strip, making the unit less usable on a power strip. In contrast, desktop power adapter takes much smaller space of the power strip when plugged in.

Step 2. Calculate the wattage of the LED strip lights to be installed.

The total wattage of the LED strip is calculated by this formula:
Wattage of the LED strip = W/m x length in meter

An example of wattage calculation:
You want to install a 12V RGB LED strip, total length to be installed is 4.5m. The LED strip has a power of 10W per meter. Then the total power is: W= 10W/m x 4.5m = 45W.

Step 3. Determine the wattage of the LED strip light adapter we need to buy.

Power adapter, like switching power supply, generally requires 20% more capacity than the wattage of the device that it supplies power for. In this way, the adapter will generate limited heat during long-time use and can ensure its lifetime.

So, in the above example, we should choose an LED strip light adapter with the power 45W x 1.2=54W. You will probably won't find an adapter with the exact wattage of 54W, then choose the next level of adapter. It is most likely to be 60W.

The power adapter's tag may not directly give its output power, but the output voltage and current. Then we need a simple calculation to get its power.

The calculation formula: W = V x A
W = output power of the adapter
V = output voltage
A = output current

For example, a power adapter has a tag as below:
Output Voltage：12V DC
Output Current：5A
Then its output power is W = 12V x 5A = 60W

Connect LED light strip to power adapter

Simliar to the power supplies, single color such as warm white, neutral white, and cool white LED strip lights can be connected directly to power adapter. Below are two popular ways to do so.
A: Directly plug the adapter DC connector into the connector of the LED strip.
B: If the LED strip has pig tailed wires, we can use a DC 5.5x2.5 coaxial barrel connector with screw terminals, then plug in the DC connector of the power adapter.

Before connecting to power adapters, RGB LED strip lights need to be connected to RGB LED controllers, while RGBW LED strips connect to RGBW LED controllers.

Power extension cable.
The power cable that comes with power adapter is typically 6 ft. If the distance between the adapter and LED strip are longer than 6 ft, a power extension cord is needed. The cross-section specification of the extension cord needs to meet the requirement of current flow, otherwise large currents passing through a small cross-section wire will generate excessive heat and are unsafe.

The current flow needed can be calculated by the specifications of the RGB strip lights using the following formula：
A = W / V
A = amperage for the extension wire
W = total wattage of the connected LED strips
V = voltage

If the power cord is not marked with the maximum current that can be tolerated, the current can be calculated based on its cross-section parameters. A simple rule of thumb can be used for the LED wire cross section: One ampere of current requires a cross section of 0.1 mm². For a current of 3.75 A, the required cross section is 0.375 mm². Typically, the next higher standard LED extension wire of 0.5 mm² is selected for safety consideration.

Please remember. LED strip light connectors can help you fast and easily install LED strips, power supplies, LED controllers. Another installation accessory recommended is the LED aluminum channel.