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How to choose a power supply for your LED strip?

If you find a suitable LED strip, but you may not be able to choose the correct power supply and cannot use your LED products. LEDs have very specific mechanisms and they require the right power source to function effectively. This article will take you through the things you need to pay attention to when choosing an LED power supply.

First make sure you can control the current of the LED strip

led strip light current

Most LED strips require a current limiting device (either a driver or a resistor) to prevent the LEDs from being overdriven. This constant-current driver or current-limiting resistor is used to regulate the current of the LED, allowing it to operate safely and maximize its lifetime. The electrical characteristics of LEDs change with temperature; if the current is not regulated, the LED can draw too much current over time. The overdraft of this current will cause the LED brightness to fluctuate, resulting in high internal heat, which eventually leads to the failure of the LED light. Most finished LED products or LED strips already have built-in drivers or resistors to regulate the current. If you’re not sure if you need a constant current source, check out this article to find out what you’re looking for. If you don’t have a current limiting device, the first step is to find a driver; but if your LED product already controls the current, you can follow this article to find a constant voltage power supply.

Constant voltage power supply

A constant voltage power supply can be used to power LED lights that already have resistors or constant current drivers in the system. These types of products usually require a constant DC voltage. Consider yourself lucky if you run on battery power or happen to have a constant DC voltage sufficient for your lights. Most of the time this will not be the case and you will need a power supply to convert the power to a safe DC voltage for your lights to use. For example, the LED flexible light strip has an onboard current limiting resistor, if you want to install it in your car, you don’t need any power supply, the 12V power supply provided by the car battery can fully meet your lighting needs. But in order to use these strips at home, an AC to DC converter is required, which converts the standard household voltage of 120VAC/220VAC to 12VDC.

1. Determine the LED product voltage

5V-or-12V-led-strip

First of all, you need to figure out what the voltage of the LED strip is. Most LED strips on the market operate at 12V DC. The others are mostly 5V and 24V DC.

If you’re still unsure, another way to confirm is to look at the product photos. Most LED strips will have a marking that says 12V or 24V.

First, consider the voltage requirements of your lamps. If your LED needs 12V to work, use a 12V driver; if it uses 24V, use a 24V driver, etc. When choosing a driver for a constant-current LED, you must also consider the LED’s current output, measured in amps or milliamps. In short, make sure your driver will achieve power output within the specified range of your lamp: consider voltage and current ranges for constant current drivers, and simple voltage ranges for constant voltage drivers.

2. Determine the power consumption of LED products

First, find out how many watts your lights will consume. If you wish to run more than one meter of strip with one power supply, you must add the wattages to find the total wattage used. Make sure you have a big enough power supply by giving yourself a 20% buffer of the total wattage calculated from the LEDs. This can easily be done by multiplying the total wattage by 1.2 and then finding a power supply rated for that wattage.

Next, calculate the length of the LED strip to be installed and multiply by the wattage per meter of the LED strip. For example, if you want to install a 5-meter LED strip with a power of 16 w/m, the power of the strip is: 5m x 16 w/m = 80W.

Then, determine the wattage of your desired LED strip power supply. It is not recommended to use the power supply to its maximum capacity as this will cause the power supply to heat up and shorten its lifespan. Expect to choose at least 20% more capacity.

For example, the power supply for the above LED strip should be at least: 1.2 x 80W = 96W. However, there is no power supply that fully meets this specification. So we choose the next level, such as a higher output power supply, 100W.

An LED power supply with higher output will not damage the LED product as it only consumes the required power.

3. For indoor or outdoor use

You have to know where you are using the led lights. Outdoor or indoor, wet or dry places. If you’re using it outdoors in a damp place, then you’ll need a waterproof power supply. If it is used indoors, such as ceilings, kitchen cabinets, TV cabinets, etc., a non-waterproof power supply is sufficient.

waterproof power supply

We can tell from the appearance of the power supply. Usually the casing is plastic or aluminium and the casing is sealed like an airtight can. Typically, it uses silicone sealant to seal electronic components.

Non-waterproof power supply

Non-waterproof LED drivers typically look like this. The housing is made of aluminum and has heat dissipation. For the same wattage, non-waterproof drives are less expensive than waterproof drives.

4. Do you need a dimmable power supply?

Most LED dimmers and controllers are 12V or 24VDC and need to be installed between the power supply and the light strip, meaning the dimmer or controller is installed after the driver or power supply.

However, if you plan to install a new AC dimmer before the LED driver, or if you want to take advantage of the TRIAC dimmer switch already installed, you will need a dimmable power supply, i.e. you will need to install the dimmer before installing the power supply. It is often said that using existing TRIAC dimmers is suitable for quick and inexpensive installations for new and retrofit work. This statement is inaccurate for the installation of LED light strips, because dimmable power supplies are much more expensive than non-dimmable power supplies, and LED dimmers for light strips are not expensive. So, using existing dimmers is supposed to save money, but the cost savings is offset by an expensive dimming power supply, and the total cost may be higher.

Both constant current and constant voltage LED strips and drivers can be made dimmable, but both must specify in the product data sheet that they are dimmable. If dimming is not mentioned in the product spec sheet, it is safe to assume that the product is not dimmable, and the same is true for household LEDs with internal drivers. Dimmable external drivers usually require an external dimmer or other dimming control device specified in the product data sheet to work.

dimmable-LED-power-supply

5. Efficiency

The efficiency of the power supply indicates the amount of power that is actually used to light the LEDs. The higher the efficiency percentage of the power supply – the more power you end up saving. For LED product applications, it is better to choose a power supply with an efficiency of 80% or higher.

6. DimensionsT

When choosing a power supply for your LED project, it is important to know where or where it needs to be installed. It has to be small enough to fit in the space provided if you wish to fit it into the product you are making. If it’s outside of the app, it should have a way to mount it nearby. Power supplies are available in many different sizes and shapes to suit your needs.  

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