BLU Advance A5 Plus LTE Replacement Battery 3.8V 3100mAh

BLU Advance A5 Plus LTE — 3.8V Li-Polymer Replacement Battery (C826734320P)

This 3.8V, 3100mAh Li-Polymer battery replaces the original cell in the BLU Advance A5 Plus LTE (A0031WW) and Grand XL (G0031WW). It matches the OEM part number C826734320P and fits the same connector and bay dimensions at 82.42 x 66.74 x 4.00mm. Swap it in when the original cell can no longer hold a charge through a normal day of calls and screen use.

• Advance A5 Plus LTE and Grand XL compatibility: Both the A0031WW and G0031WW share the same battery bay dimensions, connector pinout, and BMS handshake protocol — which is why a single cell covers both models. The charge IC on each device recognises the same pack ID, so no firmware workaround is needed.
• Bench tested on actual hardware: We cycled this cell on the Advance A5 Plus LTE platform and confirmed the BMS accepted the pack without a charge-refusal fault. Current draw tracked cleanly through screen-on and modem-active load states, and the protection circuit tripped correctly at the expected low-voltage cutoff.
• Fuel gauge recalibration after install: On first use after fitting this cell, disable fast charging and run one complete discharge-to-charge cycle at standard current. The fuel gauge IC in the Advance A5 Plus LTE is calibrated to the original cell's discharge curve — one full cycle at low current lets it remap to the new cell before fast charging pushes higher current into an uncalibrated pack.

Sudden shutdown at 20–30% on the replacement cell

This happens because the fuel gauge IC is still running the discharge curve from the old, degraded cell. The new cell has a steeper voltage drop under modem and display load near the bottom of its charge range — and the gauge hasn't mapped that cliff yet. The phone sees a voltage drop it doesn't expect at what it thinks is 25%, and the protection circuit shuts the device down. Run two full discharge-to-charge cycles at standard current and the coulomb counter will remap its endpoint to the new cell's actual curve.

Phone reports wrong battery percentage after cell swap

The Advance A5 Plus LTE stores its fuel gauge calibration in a register tied to the original cell's impedance profile. A new Li-Polymer cell has lower internal resistance than a worn pack, so the gauge misreads state of charge from the first boot. You'll see the percentage jump or stall at fixed points during a charge or discharge cycle. Drain the battery fully until the phone powers off on its own, then charge uninterrupted to 100% — repeat this once more and the gauge IC will have enough data to recalculate against the correct 3100mAh baseline.