Alcatel One Touch POP 4 TLp025H1 Replacement Battery 3.8V 1750mAh

Alcatel One Touch POP 4 / OT-5051 Series — 3.8V Li-ion Replacement Battery (TLp025H1 / TLp025H7)

This is a 3.8V Li-ion cell rated at 1750mAh (6.65Wh), replacing OEM part numbers TLp025H1 and TLp025H7. It fits the Alcatel One Touch POP 4, One Touch POP 4 LTE, OT-5051, and OT-5051X. The connector, physical footprint (70.65 × 61.90 × 4.30mm), and BMS communication lines match the original cell.

• OT-5051 and OT-5051X compatibility: Both variants share the same voltage rail, connector pinout, and BMS handshake protocol, so a single cell covers the full OT-5051 lineup without modification.
• Bench tested on actual hardware: We cycled this cell on an OT-5051 unit and monitored BMS charge termination. The protection circuit tripped correctly at low-voltage cutoff and charge current tapered as expected near full capacity.
• Fuel gauge recalibration after swap: On first use, disable fast charging and run one complete discharge-charge cycle at standard rate. The fuel gauge IC on the POP 4 calibrates its coulomb counter against the new cell's discharge curve — skipping this step leaves the IC reading against the old curve and percentage reporting will be inaccurate.

Sudden shutdown at 20–30% on the POP 4 after a cell swap

This is a voltage cliff issue, not a capacity problem. When the modem transmits or the screen brightness spikes, current draw rises sharply. If the fuel gauge IC is still calibrated to the old cell's discharge curve, it reads 25% state of charge while the actual cell voltage has already dropped below the BMS cutoff threshold. The BMS trips and the phone shuts down with percentage still showing on screen. One full discharge-charge cycle at standard rate lets the coulomb counter re-anchor to the new cell's actual voltage-to-capacity curve and eliminates these false cutoffs.

POP 4 not powering on after the replacement cell sat in storage

Li-ion cells self-discharge during storage, and if the cell dropped below approximately 2.5V the BMS enters a lockout state to prevent damage. The phone will show nothing — no charging animation, no response to the power button. Connect the phone to a wall charger (not a PC USB port, which may not supply enough current) and leave it for 15–20 minutes without pressing anything. The charge IC will trickle current into the cell until it clears the BMS lockout threshold, typically around 2.9V, after which normal charging resumes.