Google Pixel 4A Compatible Battery G025J-B 3.85V 3050mAh

Google Pixel 4A — 3.85V Li-Polymer Replacement Battery (G025J-B)

This is a 3.85V, 3050mAh lithium-polymer cell built to replace the original G025J-B battery in the Google Pixel 4A. It fits the Pixel 4A only — not the 4A 5G or any other Pixel variant. Voltage, capacity, and connector position match the original specification.

• Pixel 4A fitment: The Pixel 4A uses a single-cell Li-Polymer pack with a specific flex connector keyed to the mid-frame. The G025J-B connector orientation and BMS pin-out are retained here — the handshake with the Pixel 4A charge IC goes through as expected on first power-up.
• Bench tested on actual hardware: We ran this cell on a Pixel 4A unit and confirmed the BMS negotiated correctly with the charge IC. The cell accepted a full charge cycle without thermal events, and the device held lock screen and background sync load without voltage collapse.
• 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 map the new cell's discharge curve before high-current charging pushes current into an uncalibrated coulomb counter.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff issue, not a capacity fault. Under modem, screen, or GPS load, a new cell can sag below the Pixel 4A's minimum voltage threshold before the fuel gauge reads zero. The phone shuts down to protect the SoC even though the reported percentage is still high. One full discharge-charge cycle lets the fuel gauge IC recalibrate the sag curve — after that, shutdowns at 20–30% typically stop. If they persist after two full cycles, confirm the resting cell voltage reads at least 3.85V with a multimeter.

Phone warm near the battery during first charge after swap

A new high-impedance cell resists current flow more than a well-cycled one, which causes the charge IC to work harder and generate more heat in the first one or two sessions. This is normal and typically resolves after the cell's internal impedance drops across two or three full cycles. If the device feels hot to the touch — not just warm — stop charging and let it cool before resuming. After the second full cycle, charge the phone and verify it reaches 4.35V at the battery terminals before the charge IC terminates.