About this replacement
Redmi Note 14 Pro+ — 3.85V Li-Polymer Replacement Battery (BM68)
This is a 3.85V, 5600mAh Li-Polymer replacement battery for the Redmi Note 14 Pro+ and related models (24115RA8EC, 24115RA8EG, 24115RA8EI). It slots in when the original BM68 cell has degraded, lost capacity, or failed to hold charge. Capacity is 21.56Wh — matching the OEM specification.
- Note 14 Pro+ series compatibility: The 24115RA8EC, EG, and EI variants share the same battery bay geometry, connector pinout, and BMS handshake protocol — all three accept the BM68 cell without modification.
- Bench tested on actual hardware: We cycled this cell through charge and load on Note 14 Pro+ hardware. The BMS accepted the cell, reported state-of-charge correctly after one full cycle, and thermal cutoff thresholds held within spec under sustained display and modem load.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before proprietary fast-charge protocols push high current into an uncalibrated cell.
Sudden shutdown at 20–30% on the replacement BM68 cell
This happens because the fuel gauge IC still holds the old cell's discharge curve in memory. The new cell's voltage drops faster under modem and screen load than the old curve predicts. When cell voltage falls below roughly 3.5V under load, the BMS trips before the OS can register the drop — the phone cuts out even though the percentage display still shows charge remaining. One full discharge-charge cycle without fast charging forces the coulomb counter to re-anchor to the new cell's actual voltage floor.
USB-PD or proprietary fast charge not triggering after installation
On the first cycle after a cell swap, the charge IC may default to standard 5V charging and refuse to negotiate fast-charge protocols. This is a BMS self-protection behaviour — the controller won't accept elevated charge current until it has confirmed the new cell's internal resistance profile. Complete one full slow charge first. After that cycle, the charge IC re-evaluates the cell and fast-charge negotiation typically resumes at the next plug-in.