Hey PokemonFan1987,
We'd recommend reviewing the information in this article as it explains how to check if your AirTag battery needs to be replaced: How to replace the battery in your AirTag
"Find out if you need to replace the battery
When your AirTag battery is very low, a notification appears on your iPhone:

You can also check the Find My app to see if your AirTag battery needs to be replaced:
- Open the Find My app.
- Tap the Items tab.
- Tap the AirTag whose battery charge you want to check.
- If the charge is very low, Low Battery appears under the name of your AirTag.
"
If you're still having issues after replacing the battery, we'd recommend contacting Apple Support for further assistance here: Get Support
Thanks!