Choosing the right power supply for LED strip lighting can be a bit trickier than you’d expect. Factors such as wattage and dimmability play key roles in the selection process, and oftentimes, there is more than one power supply that will work for your particular project. There’s nothing worse than ordering something online and then realizing you don’t have the parts needed to make it work. This article aims to give you all of the information necessary to feel confident that you have what’s needed to power your LED strip lights before you purchase them.
Let’s start with the basics. The function of a power supply is to provide the correct amount of electrical current to electronics so that they work like they are supposed to and don’t overheat or fail prematurely. Whether it’s your cell phone, laptop, or in this case, LED strip lights, you’ll need something to take the 120 volts of alternating current (AC) from your wall outlet and convert it into a lower voltage of direct current (DC) that your LED strips (or other electronics) require to run. Think of trying to fill up a water balloon with a fire hose: too much water flowing too quickly—pop! The power supply regulates the flow of current to your strip to ensure optimal functionality.
Factors to consider when selecting a power supply:
1) Power consumption
Before we learn how to calculate what power supply is needed based on power consumption, you should understand what contributes to the amount of power a light strip consumes. There are two factors that play a role in this: 1) Density of LEDs per foot of strip (measured in SMDs/foot) Strips with more LEDs per foot will consume more power. 2) LED size Larger LEDs will consume more power. In short, if maximum energy efficiency is what’s most important to you, choose a light strip with smaller LEDs and fewer LEDs.
It’s important to verify that the 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. 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 LED strip. After this distance, there will not be enough voltage present to light the next length of strip. This varies depending on the type of strip and length being used. Usually, a single-density strip (nine or less LEDs per foot) will need to run back to a power source every 32 13/16 feet (10 meters). A high-density strip (18 or more LEDs per foot) will need to run back to a power source every 16 3/8 feet (5 meters). Please refer to “Max Run” in the specifications table of the strip light to determine how many can be run continuously without a parallel run back to power.
If your LED strip lighting is dimmable and you wish to adjust its brightness, you’ll need to be sure that the power supply you choose is capable of dimming. All of our power supplies are labeled as to whether or not they’re dimmable. For more on dimmability and types of dimming, check out this post.