Interestingly this is from the previous PD32: PD32 Fenix Flashlight - Fenix Lighting
“If low voltage is detected, the flashlight is programmed to downshift to a lower brightness level until to Eco brightness level. When this happens at Eco output mode, the flashlight blinks three times every five minutes to remind you to replace the battery.”
So maybe it just blinks three times when it’s low. I’m very curious now so I’ve just turned mine on on turbo to run the battery down and see if it does it. I don’t have a Fenix battery but I’m really curious how they could make that work only with a Fenix battery. It’s not like there’s software in the battery, how the hell would it know?