Poco 2312BPC51H Replacement Battery 3.82V 4900mAh

Poco C61 4G Series — 3.82V Li-Polymer Replacement Battery (BN5R)

This is a 3.82V, 4900mAh (18.72Wh) Li-Polymer battery for the Poco 2312BPC51H, 2312BPC51X, and C61 4G smartphones. It replaces a degraded or failed original cell and restores full device operation. Install it when the phone can no longer hold charge through a normal day of use.

• C61 4G platform fit: The 2312BPC51H and 2312BPC51X share the same PCB layout, connector pinout, and BMS handshake as the C61 4G retail unit — one cell fits all three without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on C61 4G hardware. The BMS accepted the cell on first connection, charge IC engaged normally, and the protection circuit tripped correctly at the low-voltage threshold.
• Fuel gauge recalibration after swap: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated state.

Sudden shutdown at 20–30% on the C61 4G after a cell swap

The C61 4G's fuel gauge IC retains the discharge curve of the old cell after replacement. When the new cell's actual voltage drops faster than the stored curve predicts, the system reads enough charge remaining — until the modem or display draws a burst and the voltage collapses below the shutdown threshold. This is a calibration mismatch, not a faulty battery. Run one complete discharge down to automatic shutdown, then charge uninterrupted to 100% without fast charge enabled. After that cycle, the coulomb counter recalibrates and the reported percentage tracks the actual cell state.

USB fast charge not activating on first cycle after replacement

On first connection to a charger, the new BMS may not complete the handshake required for the phone's proprietary fast-charge protocol. The charge IC defaults to standard 5V input until it receives a valid confirmation from the battery-side BMS. This is normal on the first cycle and clears after a full standard charge completes. Once the BMS has completed one full cycle, reconnect to a fast charger — the protocol handshake will complete and fast charging will engage at the correct voltage.