I replaced the battery but it didn't charge. It was showing a red color. After about three days I thought I'd have to take it apart and see if I had done anything wrong. I didn't see how I could have. I put the new one where the old one was. But when I turned it over I found a loose screw I'd evidently overlooked. When I tightened it up, it charged properly and then I was able to tell it to clean and it set off on it's way:)
Larry told me if I'd put it in wrong, it could have fried the new battery and the roomba, too. Thanks.