Alcatel OT-C123 V1 Replacement Battery 3.7V 450mAh

Alcatel OT-C123 / OT-C123A — 3.7V Li-ion Replacement Battery (V1)

This is a 3.7V Li-ion cell rated at 450mAh (1.67Wh), built to the V1 specification for the Alcatel OT-C123 and OT-C123A. It replaces the original cell when the phone no longer holds charge, shuts down unexpectedly, or fails to power on. Physical dimensions are 41.00 × 34.50 × 4.20mm — measure your original before installing.

• OT-C123 and OT-C123A compatibility: Both variants share the same battery bay geometry, connector pinout, and BMS handshake protocol. One V1-spec cell covers both models without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the OT-C123 platform. The BMS accepted the charge handshake cleanly on the first cycle and held cutoff voltage within spec at both ends of the curve.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging if your charger supports it and run one complete discharge-to-charge cycle. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging begins — otherwise percentage readings can drift or jump early in the battery's life.

Sudden shutdown at 20–30% on the OT-C123 after a cell swap

A fresh Li-ion cell has a steeper voltage cliff than a broken-in cell. When the phone's modem fires a high-current burst — during a call or data transfer — the new cell's terminal voltage drops sharply under load. The fuel gauge IC reads that drop as a critically low state and triggers an emergency shutdown, even though the percentage display was showing 25% a moment earlier. Run two full discharge-charge cycles without fast charging; the fuel gauge IC recalibrates its model against the actual cell curve and the premature shutdowns stop.

OT-C123 won't power on after sitting in storage

Li-ion cells self-discharge over time. If the OT-C123 sat unused for several months, the cell voltage may have dropped below 2.5V — the threshold where the BMS locks out to prevent damage. The phone will show nothing when you press the power button, and a standard charger may not trigger a charge cycle because the BMS is blocking current. Connect the phone to a low-current USB source (a PC port, not a wall adapter) for 15–20 minutes; this trickle is enough to bring the cell above 3.0V, at which point the BMS re-initialises and normal charging resumes.