Vivo B-N7 X50 Pro+ Replacement Battery 3.87V 4250mAh

Vivo X50 Pro+ — 3.87V Li-Polymer Replacement Battery (B-N7)

This is a 3.87V, 4250mAh (16.45Wh) Li-Polymer battery for the Vivo X50 Pro+, X50 Pro Plus, and V2011A. It replaces the original B-N7 cell when capacity has dropped to the point where the phone no longer holds a charge through a normal day. Voltage and connector match the original spec exactly.

• X50 Pro+, X50 Pro Plus, V2011A fit: All three model designations share the same battery bay dimensions, connector pinout, and BMS communication protocol — the V2011A is the internal hardware revision code for the same physical device sold across different regions. One cell fits all three.
• Bench tested on actual hardware: We ran the B-N7 replacement through charge and discharge cycles on the V2011A board. The BMS accepted the cell, charge IC handshake completed without fault codes, and the fuel gauge IC tracked state-of-charge correctly after a full calibration cycle.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge down to auto-shutoff, then charge to 100% on standard charging. This lets the coulomb counter in the fuel gauge IC map the new cell's discharge curve before high-current charging sessions begin.

Why the Vivo X50 Pro+ shuts down suddenly at 20–30% after a cell swap

The fuel gauge IC on the X50 Pro+ uses a stored discharge curve from the previous cell to predict remaining capacity. When a new cell goes in, that curve no longer matches actual cell chemistry, so the IC underestimates how close the cell voltage is to the BMS cutoff threshold. Under high load — 5G modem, screen at full brightness, camera active — the new cell's voltage drops sharply, hits the BMS floor faster than the percentage reading suggests, and the phone cuts power. One full discharge-to-shutoff cycle forces the coulomb counter to resync against the real cell curve and eliminates the premature cutoff.

USB-PD or proprietary fast charge not working on the first cycle after replacement

Vivo's fast charge protocol requires the charge IC to negotiate current limits with the BMS on the new cell before stepping up to high-current delivery. On the first charge after installation, the IC defaults to a conservative 5V/1A profile until it confirms BMS readiness — this is normal and not a fault with the replacement cell. If fast charge still fails after the first full cycle completes, check the charge port for debris and reseat the battery connector. A confirmed handshake shows the phone reporting the fast charge icon and the battery temperature climbing gradually rather than staying flat.