The Apple Watch Series 5 40mm battery is rechargeable and made of lithium polymer (Li-ion). It is compatible with the GPS and GPS + Cellular versions of the Apple Watch Series 5 40mm.
- Type: Rechargeable lithium polymer (Li-ion) battery
- Capacity: 245 mAh
- Operating voltage: 3.85 V
- Compatibility: Apple Watch Series 5 40mm GPS, Apple Watch Series 5 40mm GPS + Cellular