When the solar cells stop generating electricity resulting from the lack of light energy, the watch stops its second hand at the position of 12 o'clock in order to avoid loosing energy. There are models which stop both the minute and second hands. (Power Save 1 mode) With getting light on the dial, the watch will come back to the normal operation.
If the above condition continues for 3 days, the watch stops the calendar as well as the second and minute hands to minimize the energy loss. (Power Save 2 mode) With getting light on the dial, the watch will come back to the normal operation. Please see the instruction manual on this function, because it varies in respective models. When you don't use your Eco-Drive watch for a long time, you could stop all the hands and calendar manually.(Manual Power Save mode) In this mode, the watch doesn't come back to the normal operation even when the dial gets light.
* In all the Power Save modes, the watch keeps the time inside.
* The functions vary in respective models. For further information, please see your instruction booklet