English to Japanese Marketing Mechanics / Mech Engineering 腕時計

The watches are equipped with a special lithium-ion battery that is continuously recharged by a solar cell. The solar cell is printed and used as a clock face. This watches can run with a fully charged battery 150-240 days, without being further charged by light. XXXXXX calls this dark period reserve. Some models have a ***dark power reserve ** of up to 8.7 years, made possible by the fact that the hands will stop when the clock for more than 24 hours in the dark is, while the timing goes on internally. Once again light falls on the dial, the pointer in the right position and the clock continues to run. XXXXXX According to the secondary battery capacity after 20 years of a 80%.