T-Mobile LGE739 Compatible Battery 3.7V 1200mAh Li-ion

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

This 3.7V Li-ion cell replaces the original battery in the T-Mobile LGE739 and myTouch smartphone. Capacity is 1200mAh (4.44Wh), matching the factory spec. It fits directly into the battery compartment with no modification to the housing.

• LGE739 and myTouch shared platform: Both the LGE739 and myTouch run off the same voltage rail and use an identical battery bay footprint — 64.50 x 44.40 x 4.50mm. The connector orientation and BMS handshake points are identical across both variants, so one cell covers the full model range.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the LGE739 platform. The BMS accepted the cell without fault flags, and the charge IC completed a full cycle without thermal cutoff or mid-charge termination.
• Fuel gauge recalibration on first cycle: After installing this cell, disable fast charging for the first full discharge-to-charge cycle. The fuel gauge IC on the LGE739 is calibrated against the old cell's discharge curve — running one complete cycle at standard charge current lets it recalibrate against the new cell before high-current charging begins.

Sudden shutdown at 20–30% on the LGE739 after cell swap

The LGE739 fuel gauge IC stores a learned discharge curve from the original cell. When a new cell goes in, the IC does not immediately know where the real voltage floor sits. Under modem load or screen-on draw, the new cell's voltage drops faster than the IC expects, and the phone cuts off before the gauge reaches 0%. This is not a fault in the replacement cell — it is the gauge working from stale calibration data. One full discharge cycle, draining to automatic shutdown and then charging uninterrupted to 100%, resets the coulomb counter. After that cycle, shutdowns at 20–30% should stop.

Phone warm near the battery bay during the first few charges

A new Li-ion cell has higher internal impedance than a cell that has been through several charge cycles. The charge IC compensates by pushing slightly more voltage across that impedance, which generates heat at the cell surface. This is normal for the first two to three cycles and does not indicate a fault. Warmth should reduce noticeably after the cell's impedance settles through normal cycling. If the phone becomes hot to the touch — not just warm — remove it from charge and let it cool before resuming.