Samsung Galaxy M01 SM-M015 3.85V Replacement Battery HQ-61N

Samsung Galaxy M01 SM-M015 Series — 3.85V Li-Polymer Replacement Battery (HQ-61N)

This is a 3900mAh 3.85V Li-Polymer battery for the Samsung Galaxy M01, covering SM-M015, SM-M015F/DS, and SM-M015G/DS variants. It replaces OEM part number HQ-61N and restores power to the phone's processor, display, modem, and all onboard functions. Swap it when the original cell can no longer hold a full charge or fails to power the device through a normal day.

• SM-M015 variant compatibility: The SM-M015, SM-M015F/DS, and SM-M015G/DS all share the same 71.46 × 57.22 × 5.40mm cell bay and the same HQ-61N connector pinout. The BMS handshake protocol is identical across these variants, so one cell covers the full M01 lineup without modification.
• Bench tested on actual hardware: We cycled this cell on SM-M015 hardware and confirmed the BMS accepted the new cell, completed a full charge-to-cutoff cycle without error, and held voltage across a complete discharge sweep without triggering an early protection cutoff.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before fast-charge current is pushed into an uncalibrated cell.

Sudden shutdown at 15–25% on the Galaxy M01 after a cell swap

The Galaxy M01's fuel gauge IC retains the discharge curve from the old cell in its internal registers after a swap. When the new cell's actual voltage drops below roughly 3.5V under modem or display load, the IC — still expecting the degraded old cell's profile — triggers a protection shutdown before the real state of charge hits zero. This is a calibration mismatch, not a faulty battery. Run two to three full discharge-charge cycles without fast charging to let the coulomb counter rebuild its curve against the new cell. After that, the reported percentage should track the actual charge state without premature cutoff.

Fast charging not recognised on the first cycle after replacement

On the first charge cycle with a new cell, the Galaxy M01's charge IC may not negotiate the fast-charge protocol and will fall back to standard 5V charging. This happens because the BMS flags an uncalibrated cell and limits current as a precaution. Charge once at standard rate until the phone reads 100%, then disconnect. On the next charge cycle, fast charging should re-engage normally at the expected charge rate.