Garmin Enduro offers a battery performance with solar charging: up to 65 days in smartwatch mode (all-day wear, 3 hours per day outside in 50,000 lux conditions), up to 80 hours in GPS mode (assumes continuous use for entire period in 50,000 lux conditions) and up to1 year in battery saver mode (all-day wear, 3 hours per day outside in 50,000 lux conditions)