How to Choose the Best LED Strip Light Power Supply

What does an LED light strip power supply do?

A strip light power supply converts the higher AC voltage to the lower DC voltage required by the LED strip lights. LED strip lights typically operate at a low voltage of 12V or 24V DC, but most homes and buildings supply 120V AC. 

If you want to learn more, please visit our website.

What to consider when choosing a power supply:

When choosing the right power supply, you&#;ll need to know these four things:

1. The power consumption of your strip measured in

   watts per foot

2. The

   length of LED strip

   lighting your project requires

3. The

   voltage

   of your strip

4. If you want your power supply to be dimmable

You should also consider whether you want a plastic enclosed power supply or a metal enclosed AC/DC power supply. Both are designed for indoor and outdoor applications, but metal enclosed power supplies have increased durability. 

Power Consumption

The best way to determine which power supply you need is to look at the power rating of the strip light you wish to use. We use this general rule of thumb:

Make sure your power supply&#;s rated wattage is at least 20 percent higher than the total wattage of your LED strip light. To calculate this, follow this formula: 

Length of LED strip (measured in feet) x watts per foot / 0.80 = minimum rated LED power supply required to power your strip light

This will give you the minimum-sized power supply you&#;ll need to run your strips. Because power supplies are available in a variety of wattages, you&#;ll take the number you came up with and find the closest power supply that has a wattage rating higher than that number.

Let&#;s take a look at a step-by-step example:

1. You&#;re looking to install 22 feet of under-cabinet lighting in your kitchen.

2. The strip consumes 3.5 watts per foot.

3. Multiply 22 feet by 3.5 watts per foot.

4. The total is 77 watts&#;meaning your strip draws 77 watts of power.

5. Then, to follow the 20 percent rule, divide 77 watts by 0.80 to get 92.4 watts. Dividing by 0.80 provides a 20% headroom to prevent your power supply from overheating and failing prematurely.

6. This means that you will need a power supply that is rated for at least 92.4 watts.

7. Because power supply wattages are offered in varying increments, you&#;ll need to round up and find a power supply rated greater than 92.4 watts. 

You can run strips on a power source rated higher than the amount needed. In fact, if you decide to add more LED strip lighting to your project in the future, having more power will come in handy. Our LED strips already have current-limiting resistors built into the strip, so they will only draw as much current as they require. The extra wattage of the power supply will not be used, which will allow your lighting system to run cooler and more efficiently. If you run your power supply over its capacity, this will cause it to overheat or fail prematurely.

Voltage

It&#;s also important to verify that the output voltage of the power supply you choose is compatible with the voltage of your LED strip lighting. Also, be sure that the power supply&#;s input voltage matches that of the location it will be installed in. For example, if you have an LED strip with 12-volt DC operation that you wish to use in a 120-volt AC home wiring system, you&#;ll need a power supply that includes 120 volts in its input range and has 12-volt DC output.

Another factor to take into account for longer runs is voltage drop. A significant voltage drop is present after a certain distance of the LED strip. After this distance, there will not be enough voltage present to light the next length of the strip. This varies depending on the type of strip and length being used. Please refer to &#;Max Run&#; in the specifications table of the strip light to determine how long a strip can be run continuously without a parallel run back to power. Or, check out our blog post explaining how to prevent voltage drop over long runs.

LED Strip Lights have become a buzz word in the lighting industry, due to the multitude of uses, huge technological advancements and ability to replace nearly any other type of legacy lighting products like incandescent, fluorescent, halogen, neon and more. This article will go over the various things you need to know about LED Strip Lights, why you might use them, how to use them, industry terminology, along with tip and tricks along the way. So let&#;s get started.

What is an LED Strip Light?

This may seem like an obvious answer, or maybe not. But an LED Strip light is essentially lights mounted to a flexible circuit board (or flexible PCB). The lights, or LEDs (which stands for Light Emitting Diode) are assembled in a way that allows for lighting to be directed in a single direction, multiple directions or 360 degrees around the board. In the past, the power consumption and efficiency of these lighting diodes were big and bulky, and consumed lots of power per diode. This meant only a handful of lights could be placed on a linear strip, or the circuit board (or LEDs) would overheat. With today&#;s technological advancements, LEDs have become much smaller, far more efficient, provide better light output and quality, and less expensive. So much so, that replacing whole home lighting is now possible, just using different types of LED Strips. Before we get too far along, let&#;s get into how an LED works and what exactly it is.

How Does an LED Light Strip Work?

A Light emitting diode produces light by being energized by a voltage and current. This can be from a battery, wall power, kinetic energy or even static energy. In most cases, LEDs receive power from batteries or being plugged into home or commercial power. When LEDs first came to market, they came in 3 colors; red, green and blue. While this was fine, consumers really wanted the ability to have a white light. Scientists discovered if they applied a layer of phosphor over the LED lens, it would take the Blue light, and shift it to white. Soon after this was discovered, LEDs around the world had a boom and the LED world as we know it had launched into existence. This method of shifting the blue light to white through the element of phosphor single handedly brought LEDs to mainstream, but along with it, led us down a path of sacrifice. In the early s there was a big struggle for businesses and consumers to pick between eco-friendly LED products, and quality of light. When someone wanted a white LED light in their house or business, the only option available was the phosphor coated blue LED, that shifted the light over slightly over to the white spectrum. In its infancy, people would still see objects around them very saturated, with red and green hues becoming almost undetectable, because the light was so heavily focused blue. We now refer to that as a &#;Cool white&#; where the light is somewhere between blue and white. As nanotechnologies increased, so did the phosphor compositions used in LEDs, along with the efficiencies of the light. This meant that as LEDs got brighter, we could decrease the light more and more by adding additional layers of phosphor to the blue light to make even bigger shifts of light. When adding various pigments to the light, the blue light was able to shift so far down the light spectrum that it appeared almost yellow, or amber.  This allowed us to get a warmer feel for the light, and the light didn&#;t appear so &#;cold&#; any longer. But the biggest problem in the mid-s was still how the light made everyday objects &#;feel&#;. What is now a big buzz word in the industry, Color Rendering Index came into the mainstream lighting designer&#;s topic of conversation, when businesses and consumers had to sacrifice between &#;eco-friendly&#; or quality of light. Luckily, thanks to technology shifts, the light output of today&#;s LEDs are vastly superior to nearly any other lighting source available, and people no longer have to make the sacrifice between &#;eco-friendly&#; or quality.

What is Color Rendering Index (or CRI) and why is it important?

As LEDs first came into the lighting world, the CRI (or Color Rendering Index) was around 60, which essentially means the quality of the light output was about 60% as &#;true&#; as it would be in broad daylight. In some cases like flood lights, having a poor quality light output didn&#;t matter, as long as it provided enough lighting for safety and security. But in retail environments, restaurants, residential and other commercial uses, having a poor CRI was detrimental to the business. Through the years, CRI in LEDs continued to increase and the true nature of the light was nearly identical to daylight settings. Today&#;s LED strip lights can have an extremely high CRI, most are over 90 CRI which means it is 90% as true as daylight. As of , new lights have a CRI over 95 and some even up to a CRI of 98. In most cases, having a CRI over 90 is nearly impossible to tell the difference between natural daylight and LED as products, food and skin tones appear very accurate. The light output in nearly any setting is beautiful with a CRI of over 90.

LED Strip Types

In , there was basically one type of LED chip (sometimes called LED diode or LED module) you could buy, which was a LED. Today there are tons of different types of LED chips; RGB, , , , WS, the list goes on. While this seems super confusing at the beginning, there&#;s still hope for you, grasshopper. When referring to LED technology, the numbers used correspond to the overall dimensions of the diode itself, so a LED is actually just an LED that is 5.0mm x 5.0mm square. Conversely, a LED is a 3.5mm x 2.8mm LED or is 2.2mm x 1.6mm in size. Easy right?

In the past, LEDs only output light in a single color.  Today&#;s chips have 2, 3, or more LEDs mounted inside the same LED chip. This allows multiple colors or color temperatures to be combined inside a single LED housing and the combination of the colors will shine out of the diode. Many times these are referred to RGB LEDs, or Red, Green or Blue LEDs in a single housing. Today, there&#;s actually a few different types of packages with more than one diode inside the LED chip. RGBW, RGBA, RGBWW, or CCT. If RGB means there&#;s a Red, Green and Blue diode mounted inside, it wouldn&#;t come as much of a surprise that RGBW has a Red, Green, Blue and White diode mounted inside. RGBA substitutes out the white chip for an Amber chip. This is sometimes used when more rich colors are required versus wanting the ability of a bright white. RGBWW adds both a cool white and warm white chip into the same housing along with the RGB diodes.

In some instances, we see other LED types with a letter in front, like WS, WS, WS, APA102, etc. These become a little more complicated, but essentially they are a specific type of LED housing that also includes a tiny microprocessor inside each LED diode. This allows a single pixel to change the color by sending a signal to the chip. What&#;s unique about this is you can also tell that LED to send a signal to the next LED in line, so you can having multiple colored LED diodes on a single strip. Each of the designations of LED has a slightly different programming language, processor speed, and way to power them, which also allows for different uses of the light. These are often referred to as &#;Smart Pixels&#; since you can send different signals to each light in the line and change the appearance of the entire line of LEDs. 

CCT is a relatively new word in the LED world and stands for Color Changing Temperature. This includes both warm white and cool white chip inside the same housing for very specific light output.

You will get efficient and thoughtful service from BLUE DIAMOND.

Color Temperatures

Often we take color temperature for granted, but lighting designers, brands and agencies put a great deal of time in the overall feeling of the light that is seen by their audience. For instance, a cool white light is going to feel a little more like ice, and have a slight bluish hue to it. This might give their audience a more futuristic feeling, or could be more related to a hospital or office environment. On the other side, having a light output with a warmer output is going to be a little more on the yellow or orange spectrum and give off a warmer feeling of light. This might give their audience a more homely or cozy feeling. We often refer to the feeling or appearance of light on the Kelvin scale, which is typically seen rated from about K (very warm candle light) to K (very cold bluish light). Most LEDs today will have a range of about K to K. The most common lights we see are K, which is close to a standard incandescent light, or K, which we refer to as Natural White, (which is pretty much right in between warm white and cool white), or K, which has a slight bluish hue to it.

Voltage

There are many different uses for LEDs and as such, different ways to power them. Common voltages to power an LED is 5V, 12V, or 24V today. Most times, we find that 5V LEDs have an integrated IC (or microprocessor) integrated into the housing of the LED, so more often than not, if an LED Strip is being powered at 5V, it&#;s likely a &#;Smart Pixel&#; type strip. 12V used to be the most common LED strip type since it was able to be used in automotive environments without any special converters, however today&#;s most common LED Strip type is 24V. This is because LEDs can be run in longer lengths without experiencing any loss in light as it goes farther from the source of power. When powering any of these strips from the wall or main power, it is important to first understand the voltage of the light, so you can purchase the correct power source. No matter where you are in the world, there&#;s sure to be a converter of electricity, which we refer to as an AC Adapter (or power supply). It takes your home or business power and converts the power to a usable voltage that the LEDs would run at. Not to be the bearer of bad news, but just because you matched the voltage up correctly doesn&#;t mean your light will work properly. Power consumption is the other big factor in the lighting equation.

Power Consumption

Now that you have a good idea of the different types of LEDs and the voltages they run at, the next thing you need to know is how much power they consume. Generally speaking, the power consumption of an LED Strip is rated in Watts per Meter (or per foot), which is how much power each linear meter (or foot) would consume at full brightness. So if a strip says it is 14w/m (or 14 Watts per Meter), and you have 5 meters of LED tape, the TOTAL power consumption of that LED strip is 70W. There&#;s actually 3 factors to selecting power, but the math between them is all interchangeable. The third factor here is Amperage (or Amps), which is usually found on the power source, or power supply.

Power Source

On every LED Power Supply, it will show the rating of what that particular power source is rated for. If you can&#;t find it directly on the power supply, check the model number online and search for a datasheet. It will likely have the Amperage that supply is rated for. What&#;s fun about finding Watts, Voltage and Amps, is that they are all related, so it&#;s really easy to bust out your calculator and make sure you have the right supply selected. In our example above, if we are using a 24V LED Strip, and it is listed at 14w/m, and we have 5m of tape, the total consumption is 70W (14 x 5 = 70). But on our power supply, it may say 24V, but give an Amp rating, like 4 Amps (or 4A). To find out how many watts that equates to, simply multiply 24 x 4 (Voltage x Amps).

PRO-TIP: When selecting the right power supply, always leave some headroom, meaning select a supply that produces more power than the LEDs will consume. As a rule of thumb, we generally like to use a power supply that is rated for at least 20% more than the LEDs will consume.

In this example, the total wattage the power supply is rated for is 96W, which is more than 20% above our 70W consumption of the LEDs, so this supply will work great!

PRO-TIP #2: It&#;s a good idea when working with power supplies to check the datasheet on the product. Sometimes the datasheet will show the efficiency curve, or how much the power will diminish as the supply increases in temperature. Most power supplies will heat up, but other factors like where they are mounted can also play a factor in temperature. If you have an ambient temperature sensor, it&#;s a good idea to know the general temperature of where the power supply will be located so you know how efficient (or inefficient) it will be. Generally speaking the warmer the ambient temperature, the less efficient the power supply will be.

What&#;s also fun about working with Voltage, Amps, and Watts, is you can get any of the pertinent numbers if you have 2 of the 3 of them. To work backwards and find out the minimum amperage needed on your power supply, you can divide 70 / 24 (Watts / Volts), which in this case is 2.91A.

The above example is a fairly common consumption of power for a moderately bright LED used at full brightness. However some LEDs are so bright, that it&#;s hard to look at them without being dimmed, or maybe you want to provide some more ambient light around a room and want a light that sets the mood. In these cases, being able to dim your LEDs is a huge factor.

Dimming

Most LEDs will have the ability to dim, but selecting the right dimmer can be tricky on the surface, as there are many different types of dimmers from wall switch dimmers, to handheld remotes, to smart apps like Amazon Alexa and other home automation devices. Each of these use a different type of dimming mechanism to get the light to dim, so it is important to select your dimmer that is compatible with the power supply you purchase. For the most part, the most common types of dimming power supplies are Constant Current, Constant Voltage, Triac, 0-10V, or PWM. While this may sound foreign to some, let&#;s dive deeper into each of these and figure out what it all means.

Constant Current is actually pretty simple and more common for other types of lights than LED Strip lights, as most LEDs are natively Constant Voltage devices. A constant current light means it would always consume a certain power (or current), but to dim the light would mean that the voltage raises or decreases.

Conversely, Constant Voltage is the exact opposite where the voltage of the LED always remains the same, but the current being sent to the LEDs is limited, therefore the light gets brighter or dimmer by increasing or decreasing the amount of electricity being sent.

Triac (Leading Edge)

0-10V &#; This is a newer type of dimming mechanism found on more modern power supplies. This type of dimming allows for very smooth 0-100% dimming of your light by using a separate control channel to allow the conversion to be done by the power supply itself.

PWM

Probably the most common way for an LED strip to dim today is through PWM (which stands for Pulse Width Modulation). This method is sending the same voltage to the LED, but it chops up the frequency or the frame rate of the on and off period to increase or decrease the brightness.

Many dimmers on the market today operate on one (or more) of these principles. When pairing an dimmer and power supply, make sure they are using the same dimming scheme as stated above so they can dim properly. Typically using Incandescent dimmers will not dim an LED strip properly, since the consumption is so low in comparison to higher voltage lights.

Pixelization

In the past, it was hard to get away from the hot spots commonly seen on LED strip lights because there needed to be a certain distance between LEDs so they wouldn&#;t overheat. Today&#;s ultra-efficient high CRI LED chips allow us to create ultra-fine density LED strips by packing in hundreds of pixels into each linear meter (or foot) of led tape. This allows for less spacing between pixels, and allows for a more even light distribution. Even so, many brands and consumers don&#;t necessarily want to see the harsh light of the pixels. New lines of LED strips called Pixel-Free LED have emerged to combat this, by adding a secondary layer of phosphor, silicon, or other materials to diffuse the light. This allows the strip to become a direct-view light, meaning that it&#;s pleasant to look directly at the light, instead of trying to hide the light and rely on the glow that it produces.

How do you choose the right LED Lighting Strips?

Because there are so many types of LED strips, to the average user, finding the right product is like ordering their wife&#;s iced vanilla oat milk decaf latte. If you feel like that, then keep reading. There&#;s a few factors that play into the proper selection of the type of LED strip like where it is located, how bright it needs to be, and what you are applying it to. In indoor installations, many different strips will work, and most times the main factor in indoor installations is how bright the light needs to become. Dimming these is generally not a problem, so it is good to understand the brightest the strip needs to be, and work backwards from there. If there is already incandescent light or other light in place, you can read the manufacturers specifications for how many lumens the light produces. Putting it into perspective, a common incandescent 60W light bulb produces around 600 lumens. If you are intending to replace a room with 5 bulbs, you may expect the total light output of the current fixtures to be around lumens (600 x 5). Depending on how much room you have to mount the LED strip, you will want to make sure the lumen output for the total length will come close to or exceed the lumen figure to have a similar light output.

Outdoor Strip Lights

If the installation you are using is outdoors, making sure to have a IP65 or above rating on your strips is very important. An IP rating is a classification that tells the protective nature of the product. IP20 means that there is really no waterproofing or protection at all. An IP65 means that it is splash proof, generally stating that it can be used outdoors in many environments. However if the strip will be exposed to all elements, you might consider a higher IP rating, like IP67. This means the product is dust, wind, and splash proof. Achieving a rating for IP68 is important only if the lights are intended to be submerged in water.

Wrap Up

Now that you have a good idea of what an LED Strip Light is, how to use it in various installations, it&#;s time to get started on making your dream come to light. If you have any specific questions on your installation, need help selecting the proper products, or help with your next project, please feel free to contact us at or call 877.615..

If you want to learn more, please visit our website High Efficiency Constant Current LED Strips.