C645004170T BLU Advance 4.5 Compatible Battery 3.7V 1750mAh

BLU Advance 4.5 / A310 — 3.7V Li-ion Replacement Battery (C645004170T)

This is a 3.7V, 1750mAh Li-ion cell built to fit the BLU Advance 4.5 and A310 smartphones. It slots into the same compartment as the original C645004170T and reconnects to the same charge IC on the motherboard. Swap it in when the original cell no longer holds a usable charge or fails to power the phone at all.

• Advance 4.5 and A310 compatibility: Both models run the same 3.7V power rail and use the same physical connector and cell footprint. One replacement cell covers either variant without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Advance 4.5 mainboard. The BMS accepted the charge IC handshake on the first cycle and held voltage within spec across screen-on and modem-active load states.
• Fuel gauge recalibration on first use: After fitting this cell, disable any fast-charge mode and run one full discharge-to-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes into an uncalibrated state.

Sudden shutdown at 20–30% on the BLU Advance 4.5

This happens when the cell voltage drops below what the modem or display needs under load, even though the fuel gauge still reads a figure above zero. The cell hits a voltage cliff — a point where internal resistance causes a sharp voltage sag under current draw. A fresh cell with a properly calibrated fuel gauge IC eliminates this by giving the system accurate voltage data before the cliff is reached. After fitting the replacement, run one full discharge cycle so the coulomb counter resets its baseline.

Phone shows wrong battery percentage after cell swap

The fuel gauge IC on the A310 stores a discharge profile from the old cell. When a new cell goes in, that stored curve no longer matches the actual cell chemistry, so the percentage readout drifts or jumps. The fix is one full uninterrupted discharge from 100% down to automatic shutdown, then a full charge without interruption. After that cycle, the coulomb counter recalibrates against the new cell and percentage readings stabilise. Expect minor drift during that first cycle — it corrects itself once the cycle completes.