Select the power supply for LED strip 12V

As an inveterate electronics, continue to share experiences and best practices. I try to express, without technical terms, that it was clear from the child to the grannies. On this overcast day we will choose the right power supply for LED strip 12V, hereinafter abbreviated as «PSU». Of course the strip is led on 24 volts, selection and calculation principles are the same, but the most common is 12V. Voltage 24V. used for the design of high power light, it reduces the power used by the current and wire size 2 times. LED lighting is a great success replacing the familiar to us chandeliers and lamps. Lighting on the perimeter of the room looks modern and unusual.

Types of power supplys

PSU with active cooling, a round hole at the top PSU with active cooling, a round hole at the top

The shops in the old blocks can be referred to as «electronic transformer». In my youth there was no cell phones and switching power supply on the chips. I and many others do not understand the modern name of «driver» that translated from the English in general, as a «driver». In the sense, it has nothing to do with electricity. In fact, the term «power supply» and «driver» refers to different devices. PSU is a voltage source, and the driver is the source of power, such as in the LED lamp.

Passive cooling, IP20 enclosure Passive cooling, IP20 enclosure

According to the cooling system there are two kinds, active and passive:

  1. active cooling — fan installed in the housing as in the computer box. The fan helps reduce body size and increase power. But the downside is the noise from the fan, which over time will only increase. A couple of years the entire inner need to be cleaned and lubricated fan or change, a large flow of air brings a lot of dust. I am a lover of absolute silence do not use these;
  2. passive — body like a laptop power supply, or on top of closed bars.
power supply from the laptop power supply from the laptop

By execution are divided into several types:

  1. body like a laptop unit, black plastic with a sticker with the specifications. I think the best option;
  2. sealed aluminum housing for wet rooms, not afraid of water and condensate. Well established;
  3. apertured metal body and a pad used for dry areas, is mounted in an inaccessible location, preferably in a closed volume for protection against dust.
Sealed in an aluminum IP67 case Sealed in an aluminum IP67 case

As the functionality:

  1. It can be simple, providing only food;
  2. more features are built-in dimmer;
  3. It can be integrated remote control via infrared or radio channel;
  4. the most expensive are immediately dimmer and remote control, it helps to get rid of the heaps of these units in different locations.

Calculation of the power supply at 12V

Wiring for LED strip Wiring for LED strip

Draw a simple calculation, for the popular LED strip SMD 5050 3-meter, power 14,4W and has 60 led/m.

  1. We calculate the consumption of the entire strip, 3 meters
    14,4W * 3m. = 43W
  2. Adding the 20% reserve, which will go to the losses in the conductors
    43W * 1,2 = 52W
  3. We got that the minimum unit power should be 52W. The nearest suitable model usually has a 60W, respectively, and select it.

In addition to losses in wires and LED strip itself, plays a significant role and the quality of design, circuits and components for power supply. If it is an average value and is not super high quality, then these characteristics will be the maximum permissible for them it will be unstable. Here is an example of the practice, on the PSU 60W. hooked strip 55 Vt., but after 10 minutes of strip starts flashing. When heated, the electrical parameters change slightly, the voltage drops. The capacity of a little lacking. I disassembled and internal regulator voltage dropped from 12.5 to 11.5 V. It was enough for a stable and proper room lighting.

The power supply with their own hands

Electronic transformer inside Electronic transformer inside

Sometimes you need to make a small backlight LED strip in the kitchen or loggia, from the remnants of LED strip, but did not want to buy, because the costs exceed the value of all the planned construction. First comes the idea to make electronic trasnformator own hands. Buy from the Chinese version on AliEkspress not have very long to wait for delivery. But there are more interesting options which many people forget, but I always use. I will not publish here the circuit at 12V, it will write separately and in detail.

Now many devices powered by an external 12V power supply units and have a capacity of 10 to 50 watts. It may be tablets, televisions, electric shavers, laptops, computers, routers, and routers. Roughly speaking, 10W provides brightness at 700-800 lumens, which corresponds to the brightness of 60W incandescent lamp. Surely such a PSU lying around in your closet or garage. If the house you could not find, ask a neighbor, he just is.

An example of low power from 6W to 40W An example of low power from 6W to 40W

You can buy a very cheap source of nutrition on Avito. Many houses lying around which the power supply 12 volts, they do not know where to put it, it is a pity to throw away, so they sell it through an advertisement. The seller does not know its real value and puts a low or average price. Since we do not buy in the store, and on the ad, then we can negotiate. As a result of trades I buy at a symbolic price of 50-100 rubles. Beneficial to both the seller got rid of unnecessary bezdeluhi, and I bought a useful device is cheap, pay 5 times less than in the store. Is considered effective to waste time on search ads than search for details and to solder yourself.

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