Google Pixel 8 GS35E Replacement Battery 3.89V 4500mAh

Google Pixel 8 / GKWS6 / G9BQD — 3.89V Li-Polymer Replacement Battery (GS35E)

This 3.89V 4500mAh lithium-polymer cell is a direct replacement for the battery in the Google Pixel 8, GKWS6, and G9BQD handsets. It replaces OEM part numbers GS35E and G949-00574-01. Fit this battery when the original cell has degraded, causing shortened charge holds, erratic percentage readings, or unexpected shutdowns.

• Pixel 8 / GKWS6 / G9BQD platform fit: All three model designations share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The 92.50 × 45.80 × 6.00mm cell geometry matches the original cavity with no modification required.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on Pixel 8 hardware. The BMS communicated correctly with the device's charge IC and fuel gauge. No charge rejection or handshake errors were observed across USB-PD sessions.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current fast charging begins pushing current into an uncalibrated cell.

Why the Pixel 8 reports wrong battery percentage after a cell swap

The Pixel 8 uses a coulomb-counter fuel gauge IC that tracks charge state against a learned model of the original cell's discharge curve. When a new cell goes in, that learned model no longer matches actual cell behaviour. The gauge reads an offset — sometimes by 10–20% — until it relearns the curve. One full discharge from 100% to automatic shutdown, followed by a complete charge, resets the calibration baseline. After that cycle, percentage readings stabilise.

Sudden shutdown at 20–30% remaining on the replacement cell

This happens when the modem, display, or camera draws a high-current spike and the cell voltage drops below the BMS cutoff threshold momentarily — even though the gauge still shows 20–30%. It is a voltage-cliff symptom, not a capacity fault. New lithium-polymer cells can show steeper voltage sag under load until the electrolyte fully wets the electrode stack after a few cycles. If shutdowns persist beyond three full cycles, check that the battery connector is fully seated — a partial contact increases internal resistance and worsens voltage sag under load.