Voltage Drop Calculator

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Total Watts Used is the total power consumed by your LED lighting system, not the watt rating of your power supply. Please refer to the power requirement chart for your RibbonFlex Pro model to estimate the watts you are using. To more accurately measure watts used by your 12V LED lighting system, use a multimeter.

Watts = Volts x Amps

Watts is calculated by multiplying volts by amps used in your LED system. Learn how to measure amps or watts with a multimeter.

Tip: Measure voltage at the power lead end of the LED strip or where the 12V power wire is connected to your LED tape lighting while the lighting is energized. This measurement will also tell you if you have too much voltage drop. For optimum brightness, voltage should be at least 11.25 volts or better.

Wire Length is the length of your 12V power feed wire measured in feet from your power supply output to the front of the first LED strip in your lighting system.

Wire Gauge (AWG) is the thickness of wire you are using, or want to use, in your LED tape lighting system. The smaller the number, the thicker the wire.

LED light color and brightness are best when 12V power feed wires from the power supply to the LED strip, or array of strips, is delivering as close to 12 volts as possible.

Voltage drop is a natural occurrence in low voltage lighting systems. It is the gradual decrease in voltage that occurs along the length of the 12V power feed wires to the lighting, and varies depending on the type and size of the LED tape light installation. It is a function of wire length, wire thickness and the energy or total watts used by the lighting.

Voltage drop only becomes undesirable if you notice the brightness in one area of your lighting is objectionably different than in another area. With longer lengths of LED tape lighting, voltage drop also occurs along the tape light. As a practical approach, test your lighting prior to final installation.

If voltage drop appears to be a concern, shorten your 12V power feed wires or switch to a heavier gauge wire (lower AWG number), or shorten the length of your LED tape lighting. You can also consider using an additional power supply to create a second, separate installation.

Excessive voltage drop = reduced brightness and color accuracy
Shorter and/or thicker wires = higher brightness and color consistency
Longer LED tape = an increase in voltage drop