Yesterday, I went cycling at night for the first time in a while. It was on partway, but when I got home it was off. When I press the button, it lights up a little and then goes off immediately. It continues to light up normally while charging, so I think it's not the battery's lifespan. The charging indicator also immediately shows full. For those who have the same type, for parts. For those who can replace the battery, how about repairing and using it? There are various light patterns, such as flashing and constant on. You can switch between them by long-pressing or short-pressing the button. I covered the bicycle, so I took photos with my child's bicycle.