About this replacement
Google Pixel 5A / Pixel 5A 5G — 3.87V Li-Polymer Replacement Battery (G27FU)
This is a 3.87V, 4600mAh (17.8Wh) lithium-polymer cell built to fit the Google Pixel 5A and Pixel 5A 5G. It replaces OEM part G27FU directly, restoring power capacity when the original cell has degraded past usable health. The physical dimensions are 108.00 × 43.20 × 5.35mm — matching the original tray footprint.
- Pixel 5A and Pixel 5A 5G fit: Both models use the same battery tray, connector pinout, and BMS handshake protocol. The G27FU part number covers both variants — the 5G radio is on a separate board and does not affect battery compatibility.
- Bench tested on actual hardware: We ran this cell on a Pixel 5A unit and cycled it through charge and discharge under screen-on load. The BMS accepted charging current without fault flags, and the fuel gauge IC tracked state-of-charge through the full cycle without dropping out.
- First-cycle fuel gauge calibration: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging begins on an uncalibrated cell.
Sudden shutdown at 20–30% on the Pixel 5A after a cell swap
This is a voltage cliff issue, not a capacity fault. Under peak load — modem handoff, camera processing, or screen at full brightness — the cell voltage drops sharply below the BMS cutoff threshold even while the fuel gauge still reads 20–30%. The fuel gauge IC was calibrated to the old cell's discharge curve, so its percentage estimate no longer matches actual cell voltage under load. One full discharge-to-shutdown cycle followed by an uninterrupted charge to 100% lets the coulomb counter recalibrate and eliminate false shutdowns.
USB-PD fast charging not activating after battery replacement
On the first charge cycle after a cell swap, the Pixel 5A's charge IC may negotiate only trickle or standard 5V charging rather than the full USB-PD profile. This happens because the BMS on the new cell starts in a conservative state until it has completed one full cycle and confirmed cell impedance is within range. Plug into a USB-PD charger and let the first cycle complete fully without interruption. Fast charging typically activates automatically from the second cycle onward once the BMS has logged a valid baseline.