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RGBWW LED strip says it uses 24 watts per meter, but does it really?

The label on RGBWW LED strip says it consumes 24 watts per meter. That seems like a lot. Do I really need a 100 watt power supply to run just 4 meters of RGBWW LED strip?

First of all, what’s RGBWW mean? It stands for Red, Green, Blue, Cool White and Warm White. It allows you to mix any colour (and white) using a controller. Awesome!

If you turn on the Red, Green, Blue, Cool White and Warm White LEDs full power at the same time, the end result is simply WHITE! Because R, G and B together make white, plus two other white LEDs, you get powerful white.

And, when connected like this it uses 24 watts of power for every meter (39.3″) of LED strip. That’s what the label means when it says “24 watts per meter”.

BUT, the whole point of this kind of product is to mix any colour of the rainbow, not just to make blinding white – right?
It’s meant to be used together with a colour-controller with remote control or app in order to mix the colours.

So in that case, does it still use 24 watts per meter? Obviously not! For example, if only the Red light is on, it will use about 6 or 7 watts per meter. Same if only Green or Blue are turned on. Yellow is made with a mix of Red and Green (light uses “additive” colour mixing, it’s not the same as mixing paints). To keep the colours in balance, the controller will use only about 3 watts each of Red and 3 watts of Green to make yellow. This is so it doesn’t suddenly become twice as bright when you turn it yellow!

Now, you can also add some warm white and cool white to your colours in order to get a softer effect. These LEDs use about 5 watts per meter. Again if you mix warm and cool whites to get some “in-between” white, the output of these LEDs are balanced so you don’t suddenly get much more powerful light when two LEDs are mixed.

The net result is, the MOST power you can possibly draw when using a colour-controller is only 12 watts per meter, not 24 watts! Thus for a 5 meter (16.4 foot) roll of RGBWW LED strip you only need a power supply of 60 watts (12 watts x 5 meters)

Of course, you can use a higher capacity power supply, like 100 watts if you choose. No harm will be done (it won’t overdrive the LEDs). You’re just spending a bit extra money that you don’t need to, that’s all!