About this replacement
Samsung Galaxy M30s / SM-M307F — 3.85V Li-Polymer Replacement Battery (EB-BM207ABY)
This is a 3.85V, 5900mAh Li-Polymer battery for the Samsung Galaxy M30s, covering SM-M307F, SM-M307F/DS, and SM-M315F variants. It replaces OEM part EB-BM207ABY and GH82-21263A when the original cell has aged past acceptable capacity. At 85.10 × 64.30 × 6.00mm, it fits the factory battery bay without modification.
- M30s and M31 platform fit: The SM-M307F and SM-M315F share the same battery bay geometry, connector pinout, and BMS handshake protocol — which is why a single cell covers both. The fuel gauge IC on each reads the same thermistor and NTC values, so the BMS accepts the swap without throwing a hardware fault.
- Bench tested on actual hardware: We ran charge and discharge cycles on the SM-M307F using a bench power supply and a calibrated coulomb counter. The BMS held the 4.40V charge ceiling, balanced charge termination correctly, and the protection circuit tripped at the expected 2.5V floor under resistive load.
- Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging for one complete discharge-charge cycle. The fuel gauge IC was calibrated against your original cell's discharge curve — giving it one slow cycle lets it map the new cell's voltage profile before high-current charging begins.
Sudden shutdown at 20–30% on the replacement cell
This is the most common report after a cell swap on the M30s. The fuel gauge IC still holds the old cell's voltage-to-capacity lookup table, so it underestimates how quickly the new cell's voltage drops under modem or screen load. When the cell voltage sags below roughly 3.5V during a high-draw event — 5G handoff, screen-on burst, camera launch — the BMS cuts power before the OS registers the real state of charge. One full slow discharge down to auto-shutdown, followed by an uninterrupted charge to 100%, forces the coulomb counter to relearn the new cell's actual usable voltage window.
USB-PD fast charge rejected on first cycle after installation
After fitting a new cell, some M30s units revert to standard 5V/1A charging and refuse to negotiate Samsung Adaptive Fast Charge on the first connection. This happens because the charge IC re-evaluates the cell's impedance on the first cycle — a fresh, unformed cell presents higher internal resistance than the aged cell it replaced, and the charge controller defaults to conservative current limits until it completes one full charge sweep. Unplug the charger, power the phone off completely, reconnect the charger, and let it complete a full charge without interruption. Fast charging typically re-engages from the second cycle onward once the charge IC has profiled the new cell at 4.40V.