prompt to enable battery save mode


on Edge 820 once the battery was going below (i think) 10% was asking me if i want to enable Battery Save Mode, i dont see this in 830, i had two rides where it simply died, i'm not used to constantly monitor the battery level. whilst the battery on 830 is amazing, allowing me 12+ hrs rides on a single charge, not being allerted the battery is depletting is frustrating. Does anyone know how to enable this or simply doesn't exist?