About this replacement
BLU Advance L5 / A410U Series — 3.7V Li-ion Replacement Battery (C813443130L)
This is a 3.7V, 1100mAh Li-ion battery for the BLU Advance L5, L4, Advance A4 2019, A410U, and two additional compatible models. It replaces part number C813443130L and fits the same connector and form factor as the original cell. Dimensions are 84.05 × 34.15 × 4.80mm — verify against your existing battery before installing.
- Advance L4, L5, A4 2019, A410U compatibility: These models share the same battery footprint, voltage rail, and connector pinout. The BMS handshake requirements are identical across the series, so one cell covers the full range without modification.
- Bench tested on actual hardware: We cycled this cell through full discharge and charge on the BLU platform. The BMS accepted the cell without error flags, and charge termination triggered correctly at 4.2V.
- Fuel gauge recalibration on first use: After installation, disable any fast-charge mode and run one complete discharge-to-charge cycle at standard rate. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before high-current charging begins.
Sudden shutdown at 20–30% on the BLU Advance L5
This is a voltage cliff issue, not a capacity problem. At 20–30% state-of-charge, an aged or deeply cycled cell can no longer hold voltage under the combined load of the modem radio and display backlight. The voltage drops below the BMS cutoff threshold instantly, and the phone shuts off with percentage still showing. Replacing the cell resolves the cliff — the new cell holds its voltage curve flat through the lower charge range under load.
Phone reports wrong battery percentage after cell swap
The fuel gauge IC on the BLU Advance L5 stores a discharge curve calibrated to the original cell. After a swap, the IC is comparing coulomb counts against the wrong reference, so reported percentage drifts — often jumping several points or reading full when the cell is not. One full discharge from 100% down to auto-shutoff, followed by an uninterrupted charge to 100%, resets the coulomb counter reference. Do not interrupt this first cycle. After it completes, percentage reporting stabilises against the new cell's actual curve.