T-Mobile Shadow II 3.7V Replacement Battery CONV160 1100mAh

T-Mobile Shadow II — 3.7V Li-ion Replacement Battery (CONV160)

This 3.7V 1100mAh Li-ion cell replaces the original battery in the T-Mobile Shadow II (also listed as Shadow 2 and Shadow 2009). It matches the OEM part numbers CONV160 and 35H00063-13M. Capacity figure comes from product data — 4.07Wh total energy.

• Shadow II / Shadow 2 / Shadow 2009 compatibility: All three model names refer to the same hardware revision. They share the same battery bay dimensions (45.15 × 37.29 × 6.52mm), the same 3.7V nominal rail, and the same connector footprint — so one cell covers all three listings.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Shadow II platform. The BMS accepted the cell without fault flags, and charge termination triggered correctly at full cell voltage with no overcharge events recorded.
• Fuel gauge recalibration on first use: After installing this cell, disable any fast-charge mode and run one full discharge-to-charge cycle before resuming normal use. The phone's fuel gauge IC was calibrated to the old cell's discharge curve — one full cycle lets it map the new curve and report accurate percentages.

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

This is a voltage-cliff failure, not a capacity problem. When the modem or display pulls high current, a new cell with an uncalibrated fuel gauge can read 25% state-of-charge while the actual cell voltage has already dropped below the BMS cutoff threshold — typically around 3.0V under load. The phone's protection circuit sees an undervoltage event and cuts power instantly to protect the cell. Running one complete discharge cycle — down to automatic shutdown, then a full charge — lets the coulomb counter re-anchor its zero point to the new cell and eliminates most cliff shutdowns.

Phone feels warm near the battery compartment during the first charge

A new Li-ion cell starts with higher internal impedance than a broken-in cell. During the first charge cycle, the charge IC on the Shadow II pushes current into that higher-impedance cell, which converts more energy to heat than usual. This is normal and tapers off after one or two full cycles as the cell's impedance settles. If the casing stays hot to the touch past the second full charge or the phone gets hotter than warm, check that the replacement cell's dimensions match — 45.15 × 37.29 × 6.52mm — to rule out a fit issue causing pressure on the battery contacts.