About this replacement
BQ Aquaris A4.5 / M4.5 Series — 3.85V Li-Polymer Replacement Battery (2470)
This is a 3.85V, 2400mAh lithium-polymer replacement battery for the BQ Aquaris A4.5, Aquaris A4.5 4G, Aquaris M4.5, and Aquaris M4.5 4G smartphones. It replaces OEM part number 2470. Use it when the original cell no longer holds charge or shuts the phone down unexpectedly.
- Aquaris A4.5 and M4.5 platform fit: Both the A4.5 and M4.5 lines share the same battery bay dimensions, connector, and 3.85V voltage rail. The BMS handshake is identical across the 4G and non-4G variants, so one cell covers all four models listed.
- Bench tested on actual hardware: We cycled this cell on a BQ Aquaris M4.5 and confirmed the BMS accepted charge on the first connection, held the correct charge termination voltage, and passed current back to the board without fault codes.
- Fuel gauge recalibration on first use: After fitting this cell, disable fast charging and run one full discharge-to-charge cycle before normal use. This gives the fuel gauge IC time to map its coulomb counter against the new cell's discharge curve before high-current charging begins on an uncalibrated cell.
Sudden shutdown at 20–30% on the Aquaris A4.5 after a cell swap
The Aquaris A4.5 fuel gauge IC retains the old cell's discharge curve in memory after a swap. When the modem transmits or the screen peaks in brightness, current draw spikes and the new cell's actual voltage drops below what the IC predicts for that state of charge. The board reads an undervoltage condition and cuts power — even though the percentage still shows 20–30%. One full discharge-to-charge cycle forces the coulomb counter to relearn the new cell and eliminates the false floor. After calibration, the phone should reach 3.60V at reported zero percent before shutdown.
Phone will not power on after the replacement battery sat in storage
Lithium-polymer cells self-discharge slowly during storage. If this battery sat long enough to drop below 2.5V per cell, the BMS enters a protective lockout and will not pass current to the board on first connection. Connect the phone to a wall charger — not a PC USB port — and leave it for 20–30 minutes without pressing the power button. The charge IC needs to trickle current into the cell to bring it above the BMS recovery threshold, typically around 2.8–3.0V, before the board will boot.