I have a lot of battery-powered lights on my bike since I do a lot of riding in the dark. And I have noticed that the batteries for my LED wheel-lights last the longest when they are set to green. So, out of curiosity, I did some testing and this is what I found.
With the LEDs on steady, green was by far the longest lasting color:
11.5 hours – Green.
10.5 hours – Blue.
8.50 hours – Red.
7.25 hours – Yellow.
5.50 hours – Light Blue.
4.25 hours – Pink.
3.25 hours – White.
Green lasts more than 3x longer than white. So, if you don’t want to be annoyed by having to recharge your batteries frequently, green is your color.
Why is there so much difference? Because RGB LEDs have three diodes: red, green, and blue. The other colors are derived by mixing the three. So, to get pink, the circuitry turns on the blue and green diodes. To get white, it turns on all three: red, green, and blue. So, that’s why white draws the most power: all three diodes are switched on.
Also, if you set your lights to blink, they draw much less power. For example, when my lights are blinking green, they last for an astounding 27 hours.
My lights also have what I call “multimedia mode” where they cycle through all the colors and do some razzle-dazzle. In that mode, they last 6 hours.
Note: I did this testing with a used battery. The numbers above would be higher with a brand-new battery. And, of course, if you use a different brand of lights, you will likely get different numbers, though the ranking of colors should be the same.
To read about the technical aspects of LEDs, take a look at this page.