Here’s how to get it powered back up.
The charging port is in the same place in both the first- and second-generation Siri Remote.
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How Do I Know if my Apple TV Remote Is Charging?

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To check the status and current battery level, look in the menus on the Apple TV.
Open theSystemapp on your Apple TV’s home screen.
If not, a bar inside the battery symbol will show its relative charge level.

TheBattery Levelitem on this screen shows the exact charge percentage of your Apple TV remote.
How Often Do I Charge My Apple TV Remote?
The charging process itself only takes an hour or two.

How Do I Change the Battery in My Apple TV Remote?
Apple didn’t design the batteries inside the first- and second-generation Siri Remotes with replacement in mind.
However, the remote itself is not rechargeable.

If you have a 2nd generation remote, press and hold theBackbutton and theVolume Upbutton for two seconds.
If you have a 1st generation remote, press and hold theMenubutton and theVolume Upbutton for two seconds.
If you’re using an Apple remote, replace the battery.

An Apple TV automatically goes to sleep after it’s been inactive for a certain period of time.