Mike1234; Any of us can sell a used battery that tests out at 80%. The difference is that we call it "used" and I suspect that they are way less expensive than a "rebuilt" battery. Just curious, besides cosmetics and cables what is "rebuilt" on a "rebuilt" battery. I've heard some people say thay they actually cut open the cells and rebuild each cell. I've been asking people for decades if there is such thing as a "rebuilt" battery and have yet to find anyone other than the people that sell them believe that there is.
You know, most of us also sell used forklift trucks, but I don't think that people that buy them consider that those of us that sell them are "providing a valuable service".