Nokia Lumia 1320 BV-4BWA Replacement Battery 3.8V 3500mAh

Nokia Lumia 1320 — 3.8V Li-Polymer Replacement Battery (BV-4BWA)

This is a 3.8V, 3500mAh Li-Polymer cell built to the BV-4BWA spec for the Nokia Lumia 1320 Windows Phone. It fits the 6-inch Lumia 1320 directly and matches the original cell dimensions at 93.75 × 68.36 × 3.79mm. If your Lumia 1320 is shutting down unexpectedly or holding less charge than it used to, this cell replaces the degraded original.

• Lumia 1320 fitment: The Lumia 1320 uses a non-removable BV-4BWA cell on a 3.8V rail. The connector orientation and BMS pin layout on this replacement match that rail exactly, so the fuel gauge IC on the board can communicate with the new cell without throwing a fault.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Lumia 1320 board. The BMS handshake completed without error, and the charge IC accepted the cell normally across full-cycle testing. No protection tripping was observed under standard screen and modem load.
• Fuel gauge recalibration on first use: On first use after installation, disable any fast-charge accessory and run one full discharge-to-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging pushes into an uncalibrated state.

Why the Lumia 1320 reports wrong battery percentage after a cell swap

The Lumia 1320 uses a fuel gauge IC that builds its percentage model from the discharge curve of the original cell over many cycles. When you install a new cell, that learned curve no longer matches reality. The IC will report percentages based on old data until it recalibrates. Run one full uninterrupted discharge down to automatic shutdown, then charge to 100% without interruption — after that single cycle, the reported percentage tracks the new cell accurately.

Sudden shutdown at 20–30% on the replacement cell

This happens when the new cell hits a voltage cliff under simultaneous screen backlight and modem load — the board sees voltage drop below the cutoff threshold even though the fuel gauge still reads 20–30%. A fresh Li-Polymer cell can show steeper voltage sag than expected until the electrolyte fully settles after the first few cycles. If shutdowns persist past the third full cycle, check that the connector is fully seated — a loose contact raises internal resistance and worsens voltage sag under load. Target a resting voltage of 3.85–3.90V after a full charge before the first active use session.