kronin323
Font of Useless Knowledge
I have a Seiko Astron solar watch that I bought years ago. Mine has gotten to the point that it will only charge up to 50%. My lithium battery will need to be replaced. These solar watches do in fact need a battery.
Yeah, they won't last forever, but Citizen FAQ says the solar cell and secondary battery will last more than 10 years. And there's been lab tests that show the secondary battery still having 80% capacity after 20 years. Allegedly.
Don't know how the Seiko stuff compares. And, Citizen or Seiko, if you let it deplete completely it will damage the battery. Citizen's paperwork that comes with theirs is very explicit about never letting it deplete completely or it'll need replacement. I've seen others that won't charge fully because they were once completely depleted. But they still had enough of a reserve that they were ok as long as you didn't store them in a dark drawer all the time.