Tough Solar

Solar watches are powered by light. Built-in solar cells capture ambient light and convert it into energy.
The solar cells are so small and inconspicuous that they can be integrated easily into every watch face design. In analogue watches, the solar cell is often placed under the transparent dial and can capture enough light to power any function. In digital models, the solar cell is usually placed in a narrow frame around the display to generate the necessary energy.
Excess energy is stored in a rechargeable battery so that the watch can continue to work even in low-light conditions. After about 90 minutes in darkness, solar watches go into power-saving mode. The display switches off and the hands stop moving. The less movement in the watch, the less energy it consumes. However, it continues to run normally in the "background". In energy-saving mode, the watch can continue to operate without light for up to 24 months. The watch is reactivated by pressing a key or the incidence of light.