About this replacement
Nokia 4.2 (TA-1150 / TA-1157) — 3.85V Li-Polymer Replacement Battery (WT330)
This is a 3.85V, 3000mAh (11.55Wh) Li-Polymer cell for the Nokia 4.2 smartphone, covering model variants TA-1150 and TA-1157. It replaces the original WT330 when the factory cell has degraded and can no longer hold a stable charge through a full day of use. Dimensions are 69.00 × 61.20 × 4.10mm — a direct physical match for the Nokia 4.2 battery bay.
- Nokia 4.2 variant coverage (TA-1150, TA-1157): Both TA-series model codes use the same WT330 battery specification — identical voltage rail, connector pinout, and BMS communication protocol. One cell fits all three listed variants without any wiring or adapter changes.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a Nokia 4.2 unit. The BMS handshake completed on the first cycle, charge IC accepted the cell without error flags, and the fuel gauge IC registered capacity normally after a full discharge-charge pass.
- First-cycle fast charge disable: On first use after installation, turn off fast charging in the battery settings for one complete discharge-charge cycle. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging begins — skipping this step can result in inaccurate percentage readings for the first week of use.
Sudden shutdown at 20–30% on the Nokia 4.2 after a cell swap
The Nokia 4.2 fuel gauge IC stores a discharge curve learned from the original factory cell. After a cell swap, that stored curve no longer matches the new cell's actual voltage-versus-capacity profile. When the phone hits a voltage point the old curve marks as 20–30%, the new cell may actually be near its low-voltage cutoff — and the modem or display load causes voltage to sag below the BMS floor, triggering an immediate shutdown. The fix is one full uninterrupted discharge to automatic shutdown, followed by a full charge to 100%, which forces the coulomb counter to recalibrate against real cell data.
USB fast charge not activating after fitting the WT330
Some Nokia 4.2 units require the charge IC to complete one standard 5V charge cycle before it negotiates a higher-voltage fast charge protocol with a new cell's BMS. On the first charge after installation, plug into a standard 5V/1A source rather than a fast charger — this lets the charge IC confirm the new cell is stable before stepping up current. On the second charge and beyond, fast charging typically activates without issue. If fast charging still does not engage after two cycles, confirm the charger outputs at least 9V/1.67A, as the Nokia 4.2 requires that threshold to trigger its fast charge path.