About this replacement
Google Pixel 6 Series — 3.85V Li-Polymer Replacement Battery (GMSB3)
This is a 3.85V, 4500mAh Li-Polymer replacement cell for the Google Pixel 6 (GR1YH, G9S9B, GB7N6). It fits the standard battery bay and connects to the Pixel 6's charge IC and fuel gauge system. Swap it in when the original cell can no longer hold voltage under Tensor SoC and display load.
- Pixel 6 model variants covered: GR1YH, G9S9B, and GB7N6 all share the same battery footprint, connector pinout, and BMS handshake protocol — one cell covers the full production run of the base Pixel 6.
- Bench tested on actual hardware: We cycled this cell through Google's USB-PD charge negotiation, confirmed the BMS accepted the charge IC handshake on the first cycle, and verified the fuel gauge IC began tracking discharge current without faults.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current fast charging pushes current into an uncalibrated cell.
Sudden shutdown at 20–30% on the Pixel 6 after a cell swap
This happens because the fuel gauge IC is still mapped to the old cell's discharge curve. When the Pixel 6's Tensor SoC and 5G modem draw peak current, the new cell's voltage drops sharply at a point the gauge reads as 20–30% remaining. The system interprets this voltage sag as a fault and cuts power. One full discharge-charge cycle without fast charging resets the coulomb counter and maps the gauge to the new cell's actual voltage floor.
USB-PD fast charge not activating on the first cycle after replacement
After installation, some Pixel 6 units do not initiate USB-PD negotiation immediately — the charge IC defaults to slow 5W trickle charging on the first session. This is a BMS protection response to an uncalibrated cell, not a fault with the replacement battery. Connect the phone to its original charger and let it complete one full slow charge. USB-PD fast charge typically resumes from the second charge cycle onward.