About this replacement
BLU Studio X Plus / D770U — 3.8V Li-Polymer Replacement Battery (C80624260T)
This 3.8V, 2500mAh Li-Polymer cell replaces the original C80624260T battery in the BLU Studio X Plus (D770U). It fits the stock battery bay without modification and connects to the same flex cable harness. Voltage and capacity match the factory spec exactly.
- Studio X Plus / D770U fit: Both model designations share the same chassis, battery bay dimensions, and flex connector pinout. The C80624260T part number covers both. No adapter or modification needed — the cell drops straight into the original tray.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Studio X Plus platform. The BMS handshake initialised correctly with the stock charge IC, and charge termination triggered at the expected 4.35V cutoff without error flags.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before the coulomb counter locks in its reference points — skipping this step causes erratic percentage readings early on.
Sudden shutdown at 20–30% on the BLU Studio X Plus
This is a voltage cliff issue, not a capacity fault. When the modem transmits or the screen brightness peaks, current draw spikes hard. If the cell's internal resistance is elevated — common in aged Li-Polymer cells — terminal voltage drops below the BMS cutoff threshold even though the fuel gauge still shows charge remaining. The BMS trips and the phone shuts down. Replacing the cell eliminates the resistance spike. After fitting the new cell, confirm the phone stabilises through a full discharge cycle before assuming the issue persists.
Phone not powering on after the replacement cell sat in storage
Li-Polymer cells in storage self-discharge slowly. If a replacement cell ships or sits at a warehouse in a deeply discharged state, the BMS may lock out below 2.5V per cell and refuse to pass current to the board. The phone shows nothing — no charge indicator, no boot screen. Connect to a wall charger, not a PC port, and leave it for 15–20 minutes. Most BMS circuits include a trickle pre-charge path that recovers the cell once voltage climbs back above the 2.8V re-enable threshold.