Cozmo has an internal Lithium-ion battery that is charged using the included charging dock connected to a powered USB outlet.
Typical charging times for Cozmo are approximately 30 minutes, and will vary based upon the USB power source that you use.
When fully charged, that allows Cozmo to play for approximately 45 minutes. Actual playtime will vary based upon how you use Cozmo.
Cozmo's internal battery is not user serviceable, but is covered by Anki's Limited Warranty.
Cozmo's three Cubes use a 1.5 Volt / N size battery, also referred to as an E90 or LR1.
Batteries come pre-installed in Cozmo's Cubes and have a plastic pull-tab to prevent these batteries from draining during shipment. As soon as a pull-tab is removed, the Cube's batteries start loosing their charge.
Approximate battery life for each N size battery is 20-40 hours of game play. Depending on how you play with Cozmo, the batteries may not drain equally, so don't be surprised if you may have to change one battery before the others.
Cube batteries can be replaced with just a #1 Philips head screwdriver. See this FAQ for guidelines on replacing Cozmo's cube batteries.
Please note, that Cube batteries are considered disposables and are not covered by Anki's Limited Warranty.
Only use Alkaline N (1.5v E90 or LR1) batteries in Cozmo's Cubes.
DO NOT USE A23 batteries in a cube - using an A23 battery will damage the Cube beyond repair! Such damage is not covered by Anki's Limited Warranty.