Alcatel 1S Compatible Battery 3.85V 2900mAh TLp030K7

Alcatel 1S / OT-5024D — 3.85V Li-Polymer Replacement Battery (TLp030K7)

This 3.85V, 2900mAh Li-Polymer cell replaces the factory battery in the Alcatel 1S and OT-5024D smartphones. It matches the OEM part number TLp030K7 and fits the original battery compartment at 78.10 × 59.70 × 3.60mm. Install this when the original cell no longer holds enough charge to get through a normal day.

• 1S and OT-5024D compatibility: Both models run the same 3.85V battery rail with an identical connector and BMS handshake. The TLp030K7 part number covers the full production run of both variants, so one cell works across all units.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the 1S platform. The BMS held the 4.35V charge ceiling correctly and tripped undervoltage protection at the expected cutoff without false triggers.
• Fuel gauge recalibration on first use: On the first cycle after installation, disable fast charging and run the phone from 100% down to automatic shutdown, then charge fully. This gives the fuel gauge IC one clean cycle to map the new cell's discharge curve before fast charge current is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the Alcatel 1S after a cell swap

This is a voltage cliff problem, not a capacity problem. The fuel gauge IC in the 1S was calibrated to the old cell's discharge curve. When the modem transmits or the screen peaks in brightness, the new cell's voltage dips below the IC's cutoff threshold — even though the displayed percentage looks fine. The phone interprets that voltage sag as a dead cell and shuts down. One full discharge-charge cycle without fast charging resets the coulomb counter and eliminates the false cutoff.

USB fast charge not working on the first cycle after replacement

The 1S uses a USB-PD handshake between the charger and the phone's charge IC. On the first cycle with a new cell, the BMS may reject elevated charge current until it completes one baseline charge at standard rate. Plug into a standard 5V/1A charger — not a fast charger — and let it charge fully before switching to a fast charger. After that first full cycle, the fast charge protocol negotiates correctly and the charge IC accepts higher current without dropping back to trickle rate.