I used to love this phone a lot, but lately the battery is terrible and even flashing the firmware to a new start doesnt help, Goodbye Razer : r/razerphone
Battery RC30-0259 4000mAh for RAZER phone 2 1ICP4/69/81 - AliExpress
Razer OPUS X Replacement Battery: BatteryClerk.com Wireless Headset
Amazon.com: Toopower New 3.85V 3900mAh Replacement Battery for Razer Phone 2 RC30-0259 : Electronics