There are two types of batteries used in solar electronic watches: solar batteries + button batteries (disposable or rechargeable)
Solar batteries use amorphous silicon solar cells to power small devices electronics, such as solar cells. solar watches, small alarm clocks, LCD screens for various information and garden lamps, etc. are the most suitable photovoltaic devices.
A solar timer (solar clock) is a type of photovoltaic solar display device. It normally works 24 hours a day. Therefore, in addition to photovoltaic devices, a battery is also needed as an energy storage device. “Button” batteries are generally primary batteries, but there are also secondary rechargeable batteries. If a “button” battery is used on the device and is supplemented by amorp silicon battery componentshe, the energy generated by it under the action of the scattered light inside can not only power the LCD screen or other electronic display devices, but also distribute the energy to the device . battery, that is, to supplement its own power The energy consumed by the discharge. Judging from the relationship between solar cells and batteries, they work in rotation.
The system composed of solar cells, primary batteries and loads (electronic watch movement) is the key to long-term normal operation. That is to say, while ensuring the normal operation of the movement, the solar cell also maintains the primary battery as much as possible in a state of non-discharge, in particular by replenishing the energy consumed by the self-discharge of the primary battery. Therefore, these electronic watches usually do not need to replace the battery for a long time.
If it takes a lifetime, you're overthinking it. . But using it for more than ten or twenty years is not a big problem.
If you are asking about the battery, even though it is a solar watch, the rechargeable battery inside has a lifespan. However, the specific lifespan depends on the specific usage conditions and there is no absolute standard answer.
After using it for more than ten years, I don't need to replace the battery. While it is relatively expensive to use, I have seen people who only need to replace the battery after 3 to 4 years. .