Mike, so far I've only replaced one of my batteries, they say to replace them both at the same time, but I couldn't afford it. I shopped all around and ended up getting one of the Kirkland deep cycle batteries from Costco. A little early to tell but so far so good. I don't think I've ever bought anything from Costco that disappointed me, most of the products they sell seem to be good quality. Considering the low cost I'll buy another one when I need it.