This page refers to features of Anduril 2.
In voltage mode, the colors follow the same sequence, in the same order as a rainbow… with red indicating a low battery and purple indicating a full battery.
If you’re like me, you may not actually know what the colors of the rainbow are (doh!). No fret, here’s a handy reference with colors of the rainbow which represent the battery level from full down to empty:
|> 4.4V||white-ish (red+blue+green)|
u/Nelson_uk also posted a great video testing the different colors as the light goes through the different voltages.
Hope this helps you out in using your fancy enthusiast flashlights. Gotta love them Aux LEDS!