I forgot to follow up. Cygolite said they would charge me $5 or $10 to replace the battery, but instead, they sent me a whole new light, complete in the package with mount and cable and everything, even though I didn't send everything back to them as they had requested. I had lost some of the pieces. Anyway, I consider this to be very good customer service. Cygolite seems like a good company, and it sure doesn't hurt that they make their stuff right here in the US. Imagine that! They make good stuff at good prices and figure out how to do it domestically.