Hey Charles, According to the Roomba 650 trouble shooting page there could be multiple issues with your roomba. 1) Your target station is too far away or 2) There is an issue with your batttery. To fix the first issue you should move your home station to a more central location. For the battery problem I would suggest cleaning the nodes on the battery first then start to think about buying a replacement battery. You should check out the troubleshooting page at iRobot Roomba 650 Troubleshooting
Hi Charles, The troubleshooting page for the Roomba 650 talks about how to fix a roomba that is not moving. It suggest that you first check for debris in the wheel housing. If the housing is clear of all debris, it may be your motor that needs to be replaced. You should check out that page at iRobot Roomba 650 Troubleshooting