Vivo X23 Symphony Compatible Battery B-F1 3.85V 3400mAh

Vivo X23 Symphony Series — 3.85V Li-Polymer Replacement Battery (B-F1)

This is a 3400mAh Li-Polymer battery at 3.85V, rated at 13.09Wh. It fits the Vivo X23 Symphony, X23 Symphony Edition, X23 Symphony Edition Dual SIM, and V1816T. It replaces the original B-F1 cell when capacity has dropped after repeated charge cycles.

• X23 Symphony platform fit: The X23 Symphony, Symphony Edition, Symphony Edition Dual SIM, and V1816T all share the same battery bay dimensions and BMS handshake protocol. Swapping between these variants uses the same B-F1 cell — same connector, same voltage rail, same charge IC communication.
• Bench tested on actual hardware: We ran this cell through charge and discharge on the X23 Symphony platform. The BMS accepted the cell without error flags, and the charge IC negotiated correctly from the first cycle. No thermal cutoff events were recorded at standard 5V charging.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. The fuel gauge IC on the X23 Symphony is calibrated to the old cell's discharge curve. Running one slow cycle first lets the coulomb counter reset against the new cell before fast charging pushes higher current into an uncalibrated state.

Sudden shutdown at 20–30% on the replacement B-F1 cell

This is a voltage cliff issue. The X23 Symphony's modem and display together draw enough current that a new cell — before the fuel gauge IC has run a full calibration cycle — can hit a voltage floor the BMS reads as a cutoff condition. The phone shuts down even though the reported percentage says charge remains. Run one full discharge to 0% under light load, then charge uninterrupted to 100% without fast charging. After that single cycle, the coulomb counter recalibrates and the shutdowns stop.

Phone reports wrong battery percentage after cell swap

The fuel gauge IC stores a learned discharge curve for the original cell. After a replacement, that stored curve no longer matches the new cell's actual voltage-to-capacity profile, so the percentage reading drifts — often showing 100% far earlier than a true full charge, or dropping suddenly. This is not a fault with the replacement cell. A single full discharge-and-charge cycle at slow speed forces the IC to re-learn the curve against the B-F1. After one complete cycle, percentage accuracy returns to normal.