Nokia 1 BV-5V Replacement Battery 3.85V 1800mAh

Nokia 1 / TA-1047 — 3.85V Li-ion Replacement Battery (BV-5V)

This is a 3.85V, 1800mAh Li-ion replacement battery for the Nokia 1 smartphone (TA-1047). It uses part number BV-5V, the same number as the factory-fitted cell. Install it when the original battery no longer holds charge or causes unexpected shutdowns.

• Nokia 1 and TA-1047 compatibility: Both model designations refer to the same hardware platform. They share the same battery bay dimensions (59.46 × 54.90 × 4.66mm), the same 3.85V supply rail, and the same BV-5V connector footprint. No adapter or modification needed.
• Bench tested on actual hardware: We ran this cell through full charge and load cycles on the Nokia 1. The BMS accepted the charge handshake without flagging an unrecognised cell, and voltage held steady at 3.85V nominal under sustained screen-on load.
• Fuel gauge recalibration on first cycle: After fitting a new cell, the Nokia 1's fuel gauge IC is still calibrated to the old cell's discharge curve. Run one full discharge down to auto-shutdown, then charge uninterrupted to 100% before normal use. This lets the coulomb counter re-map against the new cell and report accurate percentages.

Why the Nokia 1 shows wrong battery percentage after a cell swap

The Nokia 1 uses a fuel gauge IC that tracks charge state by counting current in and out of the cell over time. That counter is calibrated to the original cell's internal resistance and capacity curve. A new cell has different impedance characteristics, so the existing calibration data no longer matches actual cell behaviour. The gauge will drift — showing 40% when the phone is close to shutdown, or 80% when it has barely been used. One complete discharge-charge cycle resets the reference points and brings the percentage reading back in line.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below the modem's minimum operating threshold under load — even though the fuel gauge still shows charge remaining. Entry-level Nokia platforms like the Nokia 1 run the modem and display at close to the same time, creating brief high-current draws. If the new cell hasn't completed a calibration cycle, the fuel gauge doesn't flag the voltage drop early enough. Run one full discharge to auto-shutdown and recharge to 100%, then check: the phone should remain stable down to single-digit percentages. If shutdowns continue below 3.5V under load, the cell is faulty — return it.