This replacement battery for my iRobot Roomba 500 series is impressive. My Roomba came back to life after its original battery died. At the moment, after a month of use, I can get 90 minutes to 2 hours of use before the vacuum returns to the docking station to charge. It also only takes a few hours to charge. Don't throw away Roomba if it won't start or will only run for a few minutes. It's most likely the battery. All you have to do is remove the side brush and four screws to access the battery compartment. No more than a few minutes of your time. Requires a Phillips screwdriver.