Gigabyte G1345 Replacement Battery 3.7V 1500mAh

Gigabyte G1345 — 3.7V Li-ion Replacement Battery (GLS-H03)

This is a 3.7V, 1500mAh Li-ion cell for the Gigabyte G1345 smartphone. It replaces OEM part numbers GLS-H03 and 29S00-60AR0-B30S. Swap it in when the original cell can no longer hold charge through a normal day of use.

• G1345 fit confirmation: The G1345 uses a fixed connector pinout and a BMS that handshakes with the phone's charge IC over a dedicated sense line. This cell matches that pinout, voltage rail, and cell dimensions (64.37 × 43.44 × 5.50mm) so the charge IC accepts it without fault codes.
• Bench tested on actual hardware: We cycled this cell through charge and load on the bench. The BMS held within spec at both high-screen and modem-active load states, and the protection circuit tripped cleanly at the expected over-discharge threshold.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one full discharge-charge cycle. The G1345 fuel gauge IC reads the new cell's discharge curve during that cycle — skipping this step leaves the coulomb counter calibrated to the old cell and percentage readings will drift.

Why the G1345 reports wrong battery percentage after a cell swap

The G1345 fuel gauge IC stores a learned discharge curve from the previous cell. When a new cell goes in, that stored curve no longer matches the actual cell chemistry. The IC keeps reading against the old model, so the percentage shown on screen drifts from reality. One full slow discharge down to auto-shutoff followed by a full charge resets the coulomb counter and aligns it to the new cell.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff issue, not a capacity problem. Under modem or screen load, the cell voltage drops sharply at low state of charge — faster than the fuel gauge predicts. The phone interprets that voltage drop as a critical low and cuts power before the displayed percentage reaches zero. Run two or three full discharge-charge cycles without fast charging; once the fuel gauge IC recalibrates to the new cell curve, the shutdown threshold tracks correctly. If shutdowns persist past three cycles, check that the replacement cell resting voltage reads at least 3.6V after a full charge.