LGE739 T-Mobile Compatible Battery 3.7V 1500mAh Li-ion

T-Mobile LGE739 myTouch — 3.7V Li-ion Replacement Battery

This 3.7V 1500mAh Li-ion battery replaces the original cell in the T-Mobile LGE739 myTouch smartphone. It fits the myTouch directly, matching the original voltage and capacity spec. Dimensions are 64.50 × 44.40 × 4.50mm — confirm against your existing cell before installing.

• LGE739 myTouch platform fit: The LGE739 and myTouch share the same battery bay geometry and 3.7V voltage rail. The BMS handshake on this platform is straightforward — no proprietary authentication token, so the replacement cell is recognized on first boot without a firmware unlock.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the LGE739 platform. The BMS accepted the replacement without fault codes, and the charge IC ramped current normally through CC and CV phases.
• Fuel gauge recalibration on first use: After installing this cell, disable fast charging if available and run one full discharge-to-charge cycle before normal use. The fuel gauge IC is still calibrated to the old cell's discharge curve — one full cycle lets it map the new cell and report accurate percentages.

Why the LGE739 reports wrong battery percentage after a cell swap

The myTouch uses a coulomb counter in the fuel gauge IC to track charge state. That counter builds its model against the original cell's discharge curve over many cycles. Swap in a new cell and the IC is still running the old curve — so it misreports the state of charge until it can relearn. One complete discharge from 100% to automatic shutoff, followed by a full charge, forces the IC to reset its reference points against the new cell chemistry.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC's stored curve predicts more remaining capacity than the cell can actually deliver under load. When the modem transmits or the screen peaks brightness, current draw spikes and the cell voltage sags below the BMS cutoff threshold — even though the OS still shows charge remaining. It is not a defective cell. Run two full discharge-charge cycles and the IC recalibrates its sag model. After recalibration, shutoff voltage should track closer to 3.4–3.5V under load.