Under the direct sunlight of 5000-10,000 lumens, it can be fully charged for 2-5 hours. The battery life of eco-drive watches is generally 10-12 years. Fully charged state (display H) can operate normally in the dark for 6 months left. About 16-20 months of sleep in power-saving mode. Backlit watches will be based on the use rate of the backlight. Operating time is reduced as appropriate. The Casio Eco-Drive watch can run in total darkness for more than six months on a full charge. The eco-drive watch with power-saving function can run for more than seven years in a no-light state.