Nokia 2.1 HE341 Replacement Battery 3.85V 3900mAh Li-Polymer

Nokia 2.1 / TA-1029 — 3.85V Li-Polymer Replacement Battery (HE341 / HE338)

This 3.85V, 3900mAh Li-Polymer cell replaces the OEM HE341 and HE338 batteries in the Nokia 2.1 smartphone, including TA-1029 variants. It powers the display, modem, and processor stack at the same voltage rail as the factory cell. Swap it in when the original cell no longer holds a usable charge across a full day.

• Nokia 2.1 and TA-1029 fitment: Both the 2.1 and TA-1029 share the same PCB layout, battery connector pinout, and BMS handshake protocol — which is why Nokia used the same HE341 across both. The physical dimensions (80.84 × 60.04 × 4.76mm) match the battery bay exactly.
• Bench tested on actual hardware: We cycled this cell through full charge and load discharge on the Nokia 2.1 platform. The BMS accepted the cell without error flags, and the protection circuit tripped correctly at the low-voltage cutoff threshold during deep discharge testing.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the Nokia 2.1 after a cell swap

The Nokia 2.1's fuel gauge IC retains the discharge curve from the previous cell in memory. When a new cell is installed, the IC's stored curve no longer matches the actual cell chemistry, so the reported percentage diverges from true remaining capacity. Under modem load or screen-on bursts, the actual cell voltage drops faster than the gauge expects — the phone hits the hardware cutoff before the displayed percentage reaches zero. One full uninterrupted discharge-charge cycle forces the coulomb counter to rebuild its baseline against the new cell.

Device not powering on after the replacement battery sat in storage

Li-Polymer cells self-discharge during storage. If the cell voltage drops below approximately 2.5V per cell, the BMS enters lockout mode to prevent further discharge damage — at that point the phone will not respond to the power button or a standard USB charge attempt. Connect the phone to a charger and leave it undisturbed for 20–30 minutes; the charge IC will trickle current into the cell at a safe rate until the BMS re-initialises. Once the voltage recovers above the BMS threshold, normal charging resumes automatically.