The remote that comes with your Apple TV has a rechargeable battery inside. With typical usage, you’ll need to charge it a few times a year. An alert appears on the TV screen when the remote battery is running low. You can also check the battery level in Settings.
Note: You can continue to use the remote while it’s charging.
Go to Settings 
on Apple TV.
Go to Remotes and Devices, then select Remote.
Information about your remote appears, including Battery Level.
Depending on the model of your remote, you’ll need to charge it with either a USB-C cable or a Lightning cable (sold separately).
Connect one end of a USB-C or Lightning cable to the port on the bottom of your remote.
Connect the other end of the cable to a computer USB-C or USB port or to an Apple USB-C or USB power adapter (sold separately).
The remote takes about three hours to fully charge.