Yes. When the battery is lower than 20%, there will be a push notification sent to your phone. 
 
Also, when you launch the eufy app, there will be a low battery pop-up notification. At the same time, the smart lock will emit a voice prompt reminding you that the battery is low. Also, when you lock/unlock the door, the LED indicator light will be red and it will flash 5 times.

Can eufy Smart Lock notify you when battery is low?

Ankersolix US

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