Originally Posted by
noglider
Speaking of Cygolite, the battery in my Hotshot tail light wore out after about two years, maybe more. They don't sell replacement batteries on their website, so I sent a note to their support department to see if I could buy a replacement. I sure hope so.
Rechargeable Li-ion batteries start to lose capacity and go bad after about three years. My understanding is, this is true even if you don't use the light. It makes me wonder how long a light with a built in battery was sitting around before being shipped to a customer.