Try resetting the roomba’s software using the spot and dock buttons. Did you try plugging the roomba in directly via the charging port? Make sure that the charging contacts, home base contacts, and battery contacts are not dirty. If they are, use a clean, damp, and lint- free cloth to wipe them off. If that doesn't help, replace both the charger and the home base. If ALL of these fail, contact iRobot customer support as it is most likely a motherboard issue.

Try resetting the roomba’s software using the spot and dock buttons. Make sure that the charging and battery contacts are clear and that the battery is seated properly. If that doesn't help, make sure that the battery is suitable for the roomba (which means the battery says it’s compatible with it). If none of these steps help, contact iRobot.