About this replacement
Google Pixel 3A — 3.85V Li-Polymer Replacement Battery (G020E-B)
This 3.85V, 2900mAh Li-Polymer battery replaces the original G020E-B cell in the Google Pixel 3A. It fits Pixel 3A variants across model codes G020H, G020G, and G020E. Swap it in when the original cell no longer holds a useful charge through a normal day.
- Pixel 3A variant compatibility: The G020H, G020G, and G020E share the same 3.85V battery bay, connector pinout, and BMS handshake. One cell covers all three regional variants without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a Pixel 3A unit. The BMS accepted the cell without throwing a hardware fault, and the fuel gauge IC initialised correctly on the first full cycle.
- Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge-to-charge cycle at standard speed. This lets the fuel gauge IC build an accurate discharge curve against the new cell before high-current charging is introduced into an uncalibrated system.
Sudden shutdown at 20–30% after replacing the Pixel 3A battery
A new cell has a slightly different discharge curve than the aged cell the fuel gauge IC was trained on. When the phone loads the modem or screen at full brightness, voltage drops faster than the IC predicts — it reads a safe percentage but the cell voltage hits the cutoff floor. The result is an abrupt shutdown with charge still showing on screen. One full slow discharge-to-charge cycle forces the coulomb counter to recalibrate against the real curve of the new cell. After that cycle, shutdowns at 20–30% typically stop.
USB-PD fast charging not activating on the first cycle after swap
On the first charge after a cell swap, the Pixel 3A's charge IC sometimes stays in trickle or standard mode rather than negotiating the USB-PD fast charge contract. This happens because the IC enters a conservative mode when it cannot verify the new cell's state of health. Plug in the supplied or an 18W USB-PD charger and leave the phone untouched through a full charge to 100%. On the second and subsequent charges, the IC re-enters fast charge negotiation normally.