Redmi Note 11 5G BN5C Replacement Battery 3.87V 4900mAh

Redmi Note 11 5G — 3.87V Li-Polymer Replacement Battery (BN5C)

This 3.87V, 4900mAh Li-Polymer battery replaces the original BN5C cell in the Redmi Note 11 5G smartphone. It matches the OEM voltage rail and physical footprint — 88.60 x 64.15 x 5.00mm — so it seats correctly in the chassis without modification. Capacity is 18.96Wh, matching the stock specification.

• Note 11 5G platform fit: The BN5C is specific to the Note 11 5G's battery bay dimensions and connector orientation. Voltage tolerance on this platform is tight — the PMIC expects 3.87V nominal, and cells outside that range trigger low-voltage protection before the modem stack fully loads.
• Bench tested on actual hardware: We ran the cell through charge and discharge cycles on a Note 11 5G unit. The BMS accepted charge without tripping OVP, and the fuel gauge IC tracked state-of-charge without erratic jumps after the first full cycle completed.
• Fuel gauge recalibration after installation: On first use after swapping this cell, disable fast charging and run one full discharge-to-charge cycle at standard rate. This lets the coulomb counter recalibrate its discharge curve against the new cell before Turbo Charge pushes higher current into an uncalibrated state.

Sudden shutdown at 20–30% on the Redmi Note 11 5G after a cell swap

This happens because the fuel gauge IC is still running the discharge curve it learned from the old, degraded cell. When the new cell's voltage drops under 5G modem or display load, it hits a voltage cliff the OS doesn't anticipate — the phone cuts out even though the reported percentage looks safe. The fix is a full, uninterrupted discharge to auto-shutdown, followed by a complete charge to 100% without interruption. After that single cycle, the coulomb counter maps the new cell's curve and percentage reporting stabilises.

USB-PD or Turbo Charge not activating on the first charge after replacement

Fast charge protocols on the Note 11 5G require a handshake between the charger IC and the BMS on the new cell. On a fresh cell with no charge history, the BMS sometimes defaults to standard 5V/1A input until it completes one conditioning cycle. Plug into the original Redmi charger — third-party USB-PD adapters may not complete the proprietary handshake on the first attempt. After one full charge cycle at standard rate, reconnect the Turbo Charger and the fast charge indicator should activate at the lock screen.