When working on projects that use high-power LED strips, you may have seen or heard that the voltage drop can affect the strips. What is power drop in an LED strip? This piece tells you what causes it and how to stop it from happening.
Why the power drop in an LED strip happens
Even though it might not look like it, an LED strip (let's use 12V for this talk) is actually a bunch of groups of three LEDs that are linked in parallel.
So, even though each group of three LEDs is intended to work with 12V, LED groups that are farther from the power source will often be given less than 12V, making the light output much less bright. Why does this take place?
The first reason is that lights farther away from the power source need power to travel along a longer copper trail in order to reach them.
As the distance between the copper lines grows, so does their internal resistance. This means that less energy can reach the LEDs that are farther away from the power source.
When you move the copper traces closer to the power source, they have to carry all the current used by the LEDs further downstream. This is the second reason.
One example is an LED strip that can handle 5 Amps per line (5 meters). Almost all of those 5 Amps will go through the very first part of the strip. Four amps will still be going through this point about one metre in. Only 2 Amp will be going through at 3 meters in.
Why does this matter? Copper has a higher resistance as its current density goes up. So the 5 Amps at the beginning of the LED strip might be too much for the copper leads to handle. This would add a lot of electrical resistance right away, making the voltage to all the LEDs further down the line even lower.
Keep in mind that this also goes for the plugs and all the wires that connect the power supply to the LED strip. The linking lines need to have the right size of wire. If they don't, you may lose power before the information even gets to the LED strip!
As we saw when we looked at the voltage of LED strips, even a small drop in voltage can make them much less bright.
Things that can make the effects of an LED strip power drop worse
Current draw and copper thickness are the main things that decide how much voltage drop can happen.
How much current the LED strip draws is the most important thing. This can be changed by the length of the strip being used or how it was designed in the first place (for example, in watts per metre). You can only use about 2 amps of current with a high-power LED strip if you only use a 1-meter patch.
Most of the time, copper diameter is measured in ounces. This is the amount of copper that is needed to cover a space of 1 square foot. More electricity can flow through a wire if the copper is bigger. We suggest 2.0 oz, and 3.0 oz is better for LED strips with more power.
Is a drop in the power of an LED strip bad?
When voltage drops in an LED strip, it means that the LEDs are getting less power than was intended. This usually doesn't affect how well the LEDs work.
But a drop in voltage usually means that you are losing power because of electrical resistance, which makes a lot of heat. This could be a problem if your LED strips are put in or close to materials that don't like heat. It's possible for the voltage drop to be too high because both the 3M sticky backing and the LEDs are somewhat sensitive to heat.
How can I keep the power from dropping on my LED strips?
If you know why LED strip voltage drops, you can stop them before they happen. Too much power running through not enough copper is the cause. You can lower the current by:
Using less LED strip per power supply or adding more than one power supply to the same LED strip at different points
Choosing 24V over 12V (usually gives the same amount of light but half as much power)
Choosing a lower power level
Making the wire diameter bigger for connecting wires
It's not easy to get more copper without buying new LED strip lights. If you think voltage drop could be a problem, find out how much copper was used.
