LED Lighting Expert Written by Ben Teele | A Leader in LED Technology

Current Vs. Voltage

Current, voltage, and wattage are all terms used when determining the power needs of your LED lights. Voltage is the difference in electric potential between two points in an electrical circuit. Higher voltages cause more electricity to flow to a device. Current is the rate of the flow of electrons in an electronic circuit, measured in Amps. Wattage is a measurement for electrical power. Wattage indicates the rate at which energy flows through an electrical circuit. The total watts indicate the amount of power needed to operate an electric device. The relationship between these three is expressed by the formula: volts × amps = watts. Using basic algebra, if you have two of the three values—amps, watts, or volts—you can find the third. LEDs are designed with specific maximum limits for both voltage and current. The combination of these two values determines the total power consumption of the LED, which is expressed in watts.


What is Constant Current?

Constant current refers to a system where the current is regulated, while the voltage can vary up to a certain degree. In constant current devices, an integrated chip (IC) is used to control and limit the flow of current to the LEDs. In the case of constant current strip lights, this IC ensures that even when more LEDs are added or the run length increases, the current doesn't exceed safe levels. This prevents excess power from being pushed through the LEDs, protecting them and allowing longer runs without risking damage or inconsistent performance. Essentially, the system "chokes" the current flow to maintain stable and safe operation over extended distances.


Benefits of Constant Current

Constant current strip lights offer several key benefits. With longer maximum run lengths, there’s less need for extension wires. Using these lights is the equivalent of daisy chaining six standard (16.4ft) strip lights together saving time on large-scale installations by reducing the need for cutting and soldering, which can lower overall project costs. Integrated chips regulate light output across the entire run ensuring consistent brightness from beginning to end. The simplified design process when using constant current strip lights requires fewer accessories, further reducing expenses. Additionally, their energy-efficient technology with lower wattage per foot makes them ideal for commercial or municipal projects, improving overall performance and sustainability.


Disadvantages of Constant Current

While constant current strip lights offer many advantages, they do come with a few drawbacks. They tend to have lower lumen output compared to constant voltage options, which may not make them ideal for projects that require higher amounts of light, such as task lighting. Additionally, they cannot be used with standard dimmable power supplies and line-side dimmers, limiting your options for light control. Instead, they require a Pulse Width Modulation (PWM), low voltage switch for dimming.


What is Constant Voltage?

In a constant voltage system, the voltage supplied to the LED lighting fixture remains fixed regardless of the current. To keep the voltage consistent, resistors in the strip lights limit the flow of current to prevent the LED’s from burning out. Since the strip light voltage is fixed, the power supply must match the strip light’s voltage. If the power supply and lighting fixture are mismatched, the fixture can fail as electricity continues to flow through it improperly, leading to potential damage or burnout.


Benefits of Constant Voltage

One of the key benefits of constant voltage LED strip lights is their design flexibility, allowing for easier integration into a variety of setups and configurations. They are typically more affordable to produce compared to constant current strip lights. Additionally, constant voltage systems feature a broader range of established product lines, ensuring that users can find options that suit their specific needs.

Another significant advantage is brightness; constant voltage systems often deliver higher lumen output, making them suitable for environments that require ample lighting. They are also compatible with dimmable power supplies and standard in-wall dimmers, enabling users to easily adjust lighting levels to create the desired ambiance and functionality in a space. This compatibility enhances user experience and allows for more versatile lighting control options.


Disadvantages of Constant Voltage

One of the primary concerns when using constant voltage strip lights is voltage drop when using longer runs of LED strip lights. This drop in voltage can result in inconsistent brightness along the length of the lights, diminishing the overall effectiveness and longevity of the light strip. As a result, these strips have shorter maximum run lengths. Maximum run length refers to the maximum total amount of strip light that can be daisy chained, or connected strip to strip, with a single home-run wire connection from a power supply or controller. Distributing power evenly across larger installations can also be more challenging with constant voltage systems. This can lead to additional complexities in the design and installation process, requiring extra components and planning to ensure that all areas receive adequate power and include additional wire runs to account for these limitations. Overall, while constant voltage systems offer numerous advantages, potential users must carefully consider these factors when planning their lighting projects.


When do I need Constant Current Strip Lights?

Constant current is ideal when you need to run LED strips over long distances. It allows you to extend the run length from the typical 16 feet up to anywhere from 32 feet-98 feet (depending on the LED Strip) without needing additional wire leads run from the power supply.


Best Constant Current Strip Lights


Best Constant Voltage Strip Lights


Best applications for Constant Current Strip Lights

  • Corridors and Hallway Lighting: In long corridors or hallways, constant current systems can provide continuous illumination for accent lighting while minimizing the risk of voltage drop over extended lengths. This ensures that the lighting remains consistent throughout the space, enhancing visibility and safety.
  • Crown Molding Lighting: Integrating constant current strip lights into crown molding can create a soft, ambient glow that enhances the architectural beauty of a room. This application allows for subtle illumination that can transform a space, providing elegance and warmth. The ability to run longer lengths of lights without additional home run wire connections makes constant current a perfect choice for this decorative application.
  • Cove Lighting: Like crown molding, cove lighting involves placing LED strips in recesses along walls or ceilings to create indirect lighting effects. Constant current systems ensure a uniform light output, enhancing the overall ambiance while avoiding hot spots or uneven lighting.
  • Safety Stair Tread and Step Marking: Safety is important in any environment, and constant current lighting can effectively illuminate stair treads and edges. This application helps enhance visibility, reducing the risk of accidents in low-light conditions. The reliable brightness provided by constant current systems ensures that each step is well-lit, improving safety for occupants and visitors.
  • Toe Kick Lighting: Installing constant current lighting under cabinets or along the base of furniture (toe kick lighting) adds a functional and aesthetic touch to any space. This type of lighting not only enhances the overall design but also provides additional illumination for pathways, making it easier to navigate in dimly lit areas. Constant current strip lights reduce wiring needs, ensuring smoother and quicker installations.