GK40 Motorola Moto G4 Play Compatible Battery 3.8V 2700mAh

Motorola Moto G4 Play / XT1607 Series — 3.8V Li-Polymer Replacement Battery (GK40)

This is a 3.8V, 2700mAh Li-Polymer replacement battery for the Motorola Moto G4 Play. It fits the XT1607, XT1609, and XT1600 variants, along with over 30 additional sub-models that share the same GK40 form factor. OEM part numbers GK40, SNN5967A, and SNN5967B all map to this cell.

• XT1607 / XT1609 / XT1600 compatibility: These variants share the same battery bay dimensions, connector pinout, and BMS handshake protocol. Swapping between them does not require a firmware change — the charge IC reads the same cell chemistry identifier across all three boards.
• Bench tested on actual hardware: We ran this cell through the G4 Play charge IC under full modem and display load. The BMS held the correct cutoff voltage and did not trip at low state-of-charge under screen-on stress.
• 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 charging is applied to an uncalibrated cell.

Why the Moto G4 Play reports wrong battery percentage after a cell swap

The G4 Play uses a coulomb counter in the fuel gauge IC that is calibrated to the discharge curve of the original cell. When a new cell goes in, the stored reference curve no longer matches actual cell behaviour. The percentage displayed can read high or low by 10–20% until the IC learns the new curve. One full discharge down to automatic shutdown, followed by a complete charge to 100%, resets the calibration baseline. After that cycle, percentage accuracy tightens significantly.

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

This is a voltage cliff problem, not a capacity problem. Under combined modem transmission and display load, the new cell's internal resistance causes a voltage dip that the BMS reads as a critically low cell voltage — triggering shutdown even when the coulomb counter still shows charge remaining. The fix is the same recalibration cycle: fully discharge the phone until it shuts itself off, then charge uninterrupted to 100%. After one or two of these cycles, the fuel gauge IC maps the actual voltage sag curve and the shutdowns stop. If they persist past three cycles, check that the battery connector is fully seated — a partial connection raises contact resistance and amplifies the voltage drop under load.