About this replacement
Nokia 5.3 — 3.85V Li-Polymer Replacement Battery (LC-440)
The LC-440 is a 3.85V Li-Polymer cell rated at 3900mAh (15.02Wh), built as a direct swap for the Nokia 5.3 (TA-1234). It replaces the original cell when capacity has dropped, the phone shuts down unexpectedly, or the battery no longer holds charge. Fit models share the same connector, voltage rail, and BMS handshake protocol.
- Nokia 5.3 and TA-1234 compatibility: Both model variants use the same connector pinout and 3.85V nominal rail. The BMS on each accepts the same charge-termination voltage of 4.35V, so no firmware or hardware changes are needed when swapping cells between these SKUs.
- Bench tested on actual hardware: We cycled this cell in a Nokia 5.3 unit and confirmed the BMS accepted the charge handshake without fault codes. Current draw during modem and display load stayed within the cell's continuous discharge rating throughout each test cycle.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated state. Skip this step and the OS percentage readout will drift.
Sudden shutdown at 20–30% on the Nokia 5.3 after a cell swap
The Nokia 5.3's fuel gauge IC retains the discharge curve of the old, degraded cell in its coulomb counter memory. When the new cell hits a voltage point the old curve mapped to 20–30%, the IC interprets it as empty and the OS cuts power immediately. This is not a fault with the replacement cell — it is a calibration mismatch. One full discharge to shutdown followed by a full uninterrupted charge resets the coulomb counter to the new cell's actual curve. After that cycle, the percentage readout tracks correctly.
USB-PD fast charge not activating on the first cycle after replacement
On the first charge after installation, some LC-440 cells present a higher initial impedance than the charge IC expects for fast-charge negotiation. The USB-PD controller in the Nokia 5.3 falls back to standard 5V/0.9A charging as a precaution. This is normal behaviour for a new Li-Polymer cell — it clears after one full standard charge cycle lowers the cell's internal impedance into the expected range. If fast charge still does not activate after the second cycle, check that the cable and adapter both support USB-PD at 10W or above.