Alcatel TLI009AA OT-2038X Replacement Battery 3.7V 950mAh

Alcatel OT-2038X / OT-3025 Series — 3.7V Li-ion Replacement Battery (TLI009AA)

This is a 3.7V, 950mAh Li-ion cell that replaces the TLI009AA battery in the Alcatel OT-2038X, OT-2053D, OT-2053X, OT-3025, and four additional compatible models. It restores power to devices that no longer hold a charge or fail to power on. Voltage and capacity match the original specification exactly.

• Multi-model fit — OT-2038X through OT-3025: These models share the same 3.7V single-cell architecture, physical footprint (53.20 × 34.00 × 4.60mm), and connector pinout. The BMS handshake uses the same communication line, so one cell covers the full range without modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the OT-2038X platform. The BMS accepted the cell without fault codes, charge termination triggered correctly at 4.2V, and low-voltage cutoff engaged at the expected threshold.
• Fuel gauge recalibration on first use: Disable fast charging for the first complete discharge-charge cycle after installation. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell — it prevents erratic percentage readings from the first hour of use.

Sudden shutdown at 20–30% on the OT-2038X after cell swap

This happens because the fuel gauge IC is still calibrated to the old cell's discharge curve. The new cell has a steeper voltage drop under load — when the modem or screen draws current, the cell voltage collapses below the cutoff threshold faster than the IC expects. The OS reads 25% but the actual cell voltage has already hit the shutdown floor. One full discharge-charge cycle resets the coulomb counter and aligns the reported percentage with real cell voltage.

Phone will not power on after the replacement cell sat in storage

Li-ion cells self-discharge in storage. If the cell voltage drops below approximately 2.5V, the BMS enters lockout mode to prevent damage — the phone shows nothing when you press the power button. Connect it to a wall charger, not a USB port, and leave it for 20–30 minutes without attempting to power on. Most BMS circuits will accept a trickle charge at that point and exit lockout once the cell climbs back above 3.0V.