T-Mobile Dash EXCA160 Replacement Battery 3.7V 1050mAh

T-Mobile Dash / MDA Mail — 3.7V Li-ion Replacement Battery (EXCA160)

This is a 3.7V, 1050mAh Li-ion cell that replaces the original battery in the T-Mobile Dash and MDA Mail smartphones. It matches the OEM dimensions (54.20 × 35.80 × 5.60mm) and slots into the original battery bay without modification. If your Dash is shutting down unexpectedly or no longer holding a charge, this cell restores full power capacity.

• Dash and MDA Mail compatibility: Both devices share the same battery bay dimensions, connector pinout, and voltage rail. The EXCA160 part number covers both, and the BMS communication protocol is identical across the Dash and MDA Mail hardware revisions.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on a Dash unit. The BMS accepted the charge profile without fault, held stable voltage through the discharge curve, and triggered the low-voltage cutoff correctly at the end of the cycle.
• Fuel gauge recalibration after swap: After installing this cell, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100%. The Dash's fuel gauge IC calibrated to old cell data will recalibrate its coulomb counter against the new cell's actual discharge curve on that first full cycle.

Why the Dash reports wrong battery percentage after a cell swap

The Dash uses a fuel gauge IC that tracks charge state using a coulomb counter calibrated to the original cell's impedance and discharge curve. When a new cell goes in, that reference data no longer matches the physical cell. The gauge reads percentage against the old curve, so the numbers appear inaccurate — often showing more charge than is actually available. One full discharge-to-shutdown followed by an uninterrupted full charge resets the counter to the new cell's actual parameters.

Sudden shutdown at 20–30% on a freshly installed cell

This is a voltage cliff problem, not a capacity problem. Under screen backlight or radio load, the cell voltage drops faster than the fuel gauge predicts — the gauge still shows 20–30% but the cell has already crossed the BMS low-voltage cutoff threshold of around 3.0V. It happens most often before the first full calibration cycle is complete. Run the cell down to automatic shutdown once and the gauge recalculates its cutoff prediction against the real discharge curve of the new cell.