T-Mobile Dash EXCA160 Replacement Battery 3.7V 2200mAh

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

This is a 3.7V, 2200mAh Li-ion cell built to fit the T-Mobile Dash and MDA Mail smartphones. It replaces OEM part numbers EXCA160 and 35H00080-00M. The cell matches the original's connector, physical footprint (55.82 × 35.90 × 10.11mm), and BMS communication profile.

• Dash and MDA Mail fitment: Both devices share the same battery bay dimensions, voltage rail, and BMS handshake protocol — one cell covers both platforms without modification.
• Bench tested on actual hardware: We cycled this cell on a Dash unit and confirmed the BMS accepted the new cell without a firmware lockout, held a stable charge curve, and passed the protection circuit's overvoltage and undervoltage cutoff thresholds correctly.
• Fuel gauge recalibration on first install: On first use after installation, disable fast charging and run one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before the charge IC pushes high current into an uncalibrated cell.

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

The Dash uses a coulomb-counting fuel gauge IC that retains the discharge curve from the old, degraded cell. When a new higher-capacity cell is installed, the IC's stored curve no longer matches actual cell voltage under load. At 20–30% reported charge, the new cell's real voltage under modem or screen load drops faster than the IC expects, triggering an emergency shutdown. One full discharge-charge cycle overwrites the old curve and resolves the cutoff. After calibration, the phone should read below 3.6V per cell before the first automatic shutdown.

Phone warm near the battery during the first charge after replacement

A new Li-ion cell arrives with higher internal impedance than a broken-in cell. During the first charge cycle, the charge IC pushes current into this higher-impedance cell, which generates more heat than normal at the battery contact area. This is not a fault — it reduces after one or two full cycles as the cell's impedance settles. If the device stays warm beyond the second full charge, check that the back cover is seated correctly and the cell contacts are clean and flush.