Charging my Apple Watch overnight
Does charging my Apple Watch overnight damage the battery
Apple Watch Series 4
No. The Apple Watch will stop charging when it is full, and only trickle charge as needed after that.
I've been charging my Series 4 every night for the past 3 and a half years. It still has good battery life. At the moment my Apple Watch has been off the charger since 8am (7.5 hours ago), and I have 74% battery charge left)