When I first got my E20 and didn't know whether it worked or not I tried the golf courses for batteries, but most around here use gas powered carts. I ended up calling the Interstate Battery store in Merrimack, NH and they sold me three 12V deep cycle marine batteries that had been returned under their no-questions-asked warrantee. They had tested them and found no problems so they sold them for $30 each. 12V batteries aren't ideal, but they lasted for three years of mowing and snow-throwing before I replaced them with golf cart batteries from Sam's Club.
Ben Griffith - Pepperell, MA