Motorola MT45 Edge 20 Pro Replacement Battery 3.8V 3900mAh

Motorola Edge 20 Pro — 3.8V Li-Polymer Replacement Battery (MT45 / SB18D11084)

This is a 3.8V, 3900mAh lithium-polymer replacement battery for the Motorola Edge 20 Pro and Edge 20 Pro 5G (XT2153, XT2153-1). It replaces OEM parts MT45 and SB18D11084. Fit this battery when the original cell has degraded, swells, or no longer holds adequate charge to get through normal use.

• XT2153 series compatibility: The Edge 20 Pro and Edge 20 Pro 5G share the same battery bay dimensions, connector pinout, and BMS handshake protocol. Both variants accept this 72.80 × 65.30 × 4.50mm cell without modification.
• Bench tested on actual hardware: We cycled this cell through full discharge and charge on an XT2153-1 unit. The BMS accepted the cell on first connection, protection thresholds triggered correctly at low voltage, and the charge IC reached termination without fault codes.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before the coulomb counter locks in its reference points — skipping this step causes the percentage reading to drift for several cycles.

Sudden shutdown at 20–30% on the Edge 20 Pro after a cell swap

The Edge 20 Pro's fuel gauge IC retains the discharge curve from the old, degraded cell. When the new cell hits a voltage point the IC associates with near-empty, it signals a shutdown even though capacity remains. The modem and display together draw enough current to sag the cell voltage briefly below the IC's shutdown threshold. One full uninterrupted discharge from 100% to automatic power-off, followed by a full charge, resets the coulomb counter against the new cell's actual curve.

USB-PD fast charging not activating after battery replacement

After a cell swap, the charge IC sometimes defaults to standard 5V charging on the first cycle because the BMS has not yet authenticated with the phone's power delivery controller. This is not a fault — it is the BMS running a conservative first-cycle protocol. Let the phone complete one full charge at standard rate without interruption. On the next plug-in, fast charging should negotiate correctly; verify by checking the charging indicator in Settings — it should show TurboPower or fast charge active above 5V input.