Power supply for 12V LED strip: choosing the optimal device
Using LED lighting in the interior, it is important that its operation is stable, durable and does not have a harmful effect on human vision. The correct functioning of LED devices is provided by voltage converters, which should be selected after making some calculations. A properly selected power supply for a 12V LED strip will protect the LEDs from voltage drops and premature loss of glow quality.
Types of power supplies for 12 volt LED strips
Unlike conventional incandescent lamps, LED structures cannot be connected to a 220V network. They are available with a supply voltage of 12V or 24V. As a backlight in home interiors, 12V LED strips are most in demand. To obtain the required voltage, special adapters are used – power sources that convert the voltage in the 220V network to the required value of 12V.
Before choosing a power supply for an LED strip, you should familiarize yourself with their types and characteristics. Stabilizers for LED products differ according to the following criteria:
- power – 5; 15; 30; 60; 100; 150; 200 and 350 (W);
- functionality – provide only power, with a built-in dimmer (light regulator) and/or with remote control;
- cooling system – with active and passive cooling. When the system is active, a fan is built into the housing, which makes a certain noise, which can cause discomfort;
- degree of protection – there are models sealed and leaky;
- the design of the housing is plastic, aluminum sealed for rooms with a high humidity level, metal with perforations and contact pads (used for dry rooms and requires installation in a closed place to avoid dust ingress).
Voltage stabilizers are a mandatory element of high-quality lighting, ensuring maximum efficiency of LED light sources. They supply the LEDs with electricity of the necessary parameters, protecting them from possible voltage surges and premature failure. Thanks to the power supplies, LED strips emit a uniform glow without flickering.
Power supply for 12V LED strip: calculation and connection of the device
To understand which power supply is needed for the LED strip, it is necessary to make certain calculations that take into account not only the output voltage, but also the amount of current output to the load. Therefore, for each specific backlight, it is necessary to calculate the total value of the current consumed by all LEDs in the tape.
Options for calculating the power supply for the LED strip
Before calculating the power supply for the LED strip, it is necessary to familiarize yourself with the accompanying documentation for the product, where the current consumption of one linear meter is indicated. In the absence of such data, the calculation can be made independently.
For example, we calculate the total number of LEDs for a 15 m long 12V strip with a density of 30 SMD 5050 LEDs per meter: 15 (m) x 30 (pcs.) = 450 pcs. Considering that each SMD 5050 LED consumes a current of 0.02 A (this value is given in the table of diode parameters), the total current consumption of the entire strip segment is 9A (450×0.02 = 9). Therefore, a 12V power supply with a permissible load current value of 9A will be required.
Useful advice! Overall power supplies are quite difficult to hide in the curtain structure. Therefore, for ceiling illumination, it is not recommended to use tapes with a high density of LEDs, for which powerful converters are needed.
When calculating the power of the power supply for the LED strip, we multiply the voltage and the resulting current value: 12Vx9A = 108 watts. Therefore, a stabilizer with a power of at least 108W will be acceptable. However, it should be taken into account that the unit is selected with a 20 percent power reserve, otherwise it will quickly fail from overload. This means that the required power will be: 108×1.2 = 129.6 W, i.e. for this case, the optimal choice will be a power supply for a 12V – 150W LED strip.
In addition, the converter power can be calculated using data on the main characteristics of flexible LED products. After selecting the desired type of tape, we find the corresponding power value of one meter in the table and multiply it by the total length of the backlight. Given the power reserve, we get the required power of the power supply.
Table of the main technical indicators of 12V LED strips:
|LED Class||LED size, mm2||LED strip power, W/m||Tape density, pcs/m||The value of the luminous flux, lm/m|
Example of connecting an LED strip to a power supply
It is necessary to mount the backlight to the selected surface after the power supply is connected to the LED strip. For example, we use the connection of the tape to a block whose housing is made of metal and has holes for cooling the constituent elements and the terminal strip. One of the walls of the housing is provided with a plate indicating the marking for the correct connection of wires.
Terminals with the designation “L” and “N” – phase and zero, are designed for connection to the 220V network. The grounding is indicated by the symbols “FG”. The terminals marked “G” are interconnected and designed to connect the negative output of the LED strip. Three terminals with the symbols “V” are also connected inside the adapter and a positive terminal is connected to them, respectively. It should be noted that this marking is also used on other models of converters.
To connect a single-color tape, connect the wires to the terminals, taking into account the polarity. The plug of the power cord has three wires with a brown, blue and yellow-green sheath. We attach the brown and blue wires to the “phase” and “zero” terminals, without fear of mixing them up, since they can be swapped. The yellow-green wire is connected strictly to the grounding terminal. If there is no grounding, the terminal is not used: it does not matter for the functioning of the tape.
Pay attention! The absence of a grounding wire in the mains cord is a violation of safety regulations when performing electrical work.
The above example of the wiring diagram of an LED strip to a power supply is suitable for using a backlight from a single strip up to 5 m long. If you need to connect several pieces of tape, then you need to apply a parallel connection scheme.
Diagram of parallel connection of LED strip power supplies
If, during interior decoration, it becomes necessary to highlight several decorative elements located at a certain distance from each other, parallel connection of the tape segments to the voltage converter is used. This scheme is also used when the lighting line of the structure is long enough and exceeds 5 m.
The sequential connection of the segments will lead to an uneven load distribution, as a result of which the LED strip will work incorrectly, emitting weak light on the final section. It is possible that the extreme segment of the tape will not glow at all, while the initial one will start to overheat and quickly fail. This means that it is impossible to connect the end of the first segment to the beginning of the second.
When connected in parallel, each segment of the LED strip must be connected to a power source independently of the others. This can be done by connecting each piece of tape to the power supply with separate wires. But parallel connection can be done in another way: to lay the main line of the wire from the converter, to which individual sections of the LED strip can subsequently be connected.
To ensure that the contact of the tape conductors with the main wire is reliable and strong, soldering or connection by means of special connectors is used. The use of connectors for connecting greatly simplifies the repair of the backlight in the event that malfunctions occur during operation. If the tape needs to be laid along a complex trajectory, you can use the tape itself as the main wire.
The price of a power supply for a 12V LED strip
You can buy a power supply for a 12V LED strip not only at points of sale of lighting equipment, but also on the web pages of manufacturers and organizations that sell LED products. There you can get acquainted with the range of converter models, their technical characteristics and the cost of blocks.
By contacting the site managers, you can get professional advice on how to choose a power supply for an LED strip, depending on its type and operating conditions. Experienced specialists will help you choose the right device that will ensure long-lasting and high-quality operation of the LED structure. As a rule, all products are certified and guaranteed by the manufacturer.
Pay attention! When purchasing an open type of converter, remember that it can only be used in rooms with a minimum degree of humidity and in places where there is no risk of water ingress.
Before buying a power supply for an LED strip, it is worth reviewing the cost of products offered by different companies. This will help in choosing a model with the necessary parameters on favorable terms. Approximate prices of power supplies for 12V LED strip are shown in the table:
|Converter Model||Dimensions, mm||Basic parameters||Price, rub.|
|BP interior 12V 15W IP 20||70/39/30||Supply voltage 110-220V, power 15W, equipped with a power indicator and a voltage regulator||270|
|PS 12V 35W IP 20||85/58/32||The supply voltage is 110-220V, power is 35W, has a power indicator and a voltage regulator||380|
|PS 12V 60W IP 20||159/98/38||The supply voltage is 110-220V, power is 60W, has a power indicator and a voltage regulator||540|
|BP 12V 150W IP 20||200/89/40||Supply voltage 110-220V, power 150W, equipped with a power indicator and a voltage regulator||780|
|BP waterproof 12V 30W IP 67||220/28/20||Supply voltage 110-220V, power 30W, protection from moisture and dust||560|
|BP waterproof 12V 60W IP 67||148/40/30||Supply voltage 110-220V, power 60W, protection from moisture and dust||1100|
|BP waterproof 12V 100W IP 67||202/71,2/45||Supply voltage 110-220V, power 100W, protection from moisture and dust||1670|
Sometimes there are situations when it is necessary to make a backlight on a small area along the length. Then the purchase of a power supply will cost much more than the purchase of the tape itself. In this case, you can make the converter yourself.
How to make a power supply for an LED strip with your own hands
The cost of switching power supplies for a high-power LED strip very often exceeds the flexible tape itself. However, there is an option to reduce the cost of a backlight device by using power supplies from outdated models of computers, televisions, tablets or other electrical appliances as a stabilizer. Surely such products can be found in every home.
The power of 12V converters from old electronics usually ranges from 6 to 36W. This is quite enough for the functioning of a small segment of LED lighting, for example, the area of the kitchen apron. Transformer models can be used, but they are quite heavy and their power exceeds the same tape parameter twice. As a result, when such a power supply is connected to the tape, it overheats greatly, even if it is improved by additional cooling devices.
For the normal operation of the LED strip, it is better to use switching power supplies, which, with sufficient power, weigh very little. Suitable, for example, a converter for 12V and 2A from a failed TV. The power of such a device is 24W (12×2), which allows the LED strip to work properly, and the power supply does not overheat.
Useful advice! Chargers from 5V mobile phones can be used as a power source for a small night lamp of 3-6 LEDs assembled by yourself.
It is possible to adapt an electronic ballast (current limiter), which powered a fluorescent lamp that failed, under a power supply for a 12V tape. To do this, it is necessary to convert the fluorescent lamp regulator into a step-down transformer, and then, using the circuit, connect an LED strip to it. The conversion is a winding of the secondary winding, then a secondary diode and a capacitor are added to the circuit. The main condition is that the tape power must correspond to the same ballast parameter.
Repair of the power supply for LED strips
12V voltage sources that have failed are usually amenable to adjustment. If you have enough knowledge and skills, you can try to repair the voltage converter yourself. Malfunctions can be eliminated using the power supply circuit for a 12V or 24V LED strip, since they are identical.
The most common problems in power supplies are the following:
- capacitors C22, C23 fail – they usually swell or dry out;
- transistors T10-11 are not functioning;
- The TL494 PWM controller is faulty;
- dual diode D33, capacitors C30-33.
Malfunctions of other components of converters are rare, but they are also worth checking.
To diagnose and fix problems, you need to perform the following actions:
- open the case and check the fuse. If everything is fine with it, it is necessary to measure the voltage on the capacitors (C22, C23), having previously supplied power. The value should be about 310V. Therefore, the mains filter and rectifier are normal;
- to diagnose the PWM (KA7500 chip) – if there is a voltage of 12-30V on the 12 pin, then check the chip. Otherwise, the standby voltage power supply should be checked;
- the voltage at pin 14 after the external power supply should have a value of approximately +5V. If not, it is necessary to replace the chip. That is, it is necessary to check the chip using an oscilloscope.
Repair of the power supply consists in replacing faulty elements with the same components or their analogues. In order not to face the problem of breakage later, it is necessary to follow the manufacturer’s recommendations, since exceeding the permissible load limit will cause the adapter to fail.
The right choice of power supply and related devices for LED systems guarantees durability and quality of lighting. Thanks to these devices, LED sources emit bright, flickering light that can gracefully transform your interior.