BLU C5L Replacement Battery C775443200L 3.8V 1800mAh

BLU C5L Series — 3.8V Li-ion Replacement Battery (C775443200L)

This is a 3.8V, 1800mAh Li-ion battery that fits the BLU C5L, C050, C5 2019, and C110U smartphones. It replaces the original C775443200L cell when the existing battery no longer holds a charge or has failed outright. Capacity is 6.84Wh — matching the original power budget for the device.

• C5L and C050 platform fitment: The C5L, C050, C5 2019, and C110U share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The 77.10 x 53.95 x 4.82mm cell slides into each of these models without physical or electrical conflict.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a C5L unit. The BMS accepted the cell, reported voltage correctly, and charge termination triggered at the expected threshold without error flags.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging runs against an uncalibrated reference — preventing erratic percentage readings from the first charge onward.

Sudden shutdown at 20–30% on the replacement cell

This happens because the fuel gauge IC is still using the discharge curve from the old, degraded cell. A fresh cell has a steeper voltage cliff at low charge states, so the phone reads 25% while the actual cell voltage is already dropping below the modem's operating threshold. The display and cellular radio draw spikes — particularly during a call or data burst — push the cell below cutoff voltage before the gauge catches up. Run one full discharge to 3% and a complete uninterrupted charge to 100% to force the coulomb counter to re-anchor to the new cell's actual curve.

Phone stays stuck on boot logo after cell was drained flat in storage

If the cell discharged below 2.5V during storage, the BMS enters lockout mode and will not pass current to the board even when a charger is connected. Plug in a known-working USB cable and a wall adapter — not a PC port — and leave it for 20–30 minutes without pressing the power button. The charge IC needs to trickle current into the cell until voltage recovers above 3.0V before the BMS releases the output rail and the phone can boot.