Prevent overcharging
Overcharging occurs when a battery is charged to 100% and kept connected to a charger for long periods. In those conditions, the battery keeps “topping off” instead of resting, which creates heat and stress that can wear the battery out over time. Overcharge protection keeps your battery healthy by limiting its charge to 80% if it’s been plugged in for three days.
When Overcharge protection is limiting your charge, you'll see 
To fully charge your phone from 80%, just disconnect it from the charger and plug it in again.
To turn this feature on or off:
- Go to Settings > Battery > Overcharge protection.
- Turn it on
