Citizen men's and women's Eco-Drive watches are powered by natural and artificial light. Light is absorbed through the crystal and turned into energy in the solar conversion cell. The Eco-Drive never needs a battery and can operate for up to 6 months in the dark. Citizen guarantees that their Eco-Drive watches will last a lifetime. If your watch has stopped due to lack of light, recharge it to get it working again.

Find the movement caliber of your watch on the back of the case. The movement caliber is a four digit number and appears to the left of the type of material of the watch, such as "st. steel."

Enter the movement caliber in the blank on the Recharge Guide page on the Citizen website (see Resources). Click "Get Recharge Guide."

Put your watch in natural light for the amount of time recommended by the recharge guide. Artificial light is not strong enough to fully charge a depleted battery, but is sufficient for keeping the battery charged. You will see the amount of time needed to fully charge a depleted battery on a sunny day and a cloudy day under the headings, "Outdoors, Sunny" and "Outdoors, Cloudy." All Eco-Drive watches take roughly three hours of exposure to natural light on a sunny day to fully charge.