Like I said, we’ve been buying them for years and I’ve only had to use the warranty once meaning one battery out several didn’t last past the one year warranty. They tend to last just as long or longer than the Walmart batteries I’ve bought. But the point of my original post was my fairly new NOCO Genius 10 charger/maintainer malfunctioned and overcharged the battery causing it to overheat and smell like rotten eggs. I wondered if it was the battery but it was the charger malfunctioning.