About this replacement
BLU Studio C / D830 Series — 3.8V Li-Polymer Replacement Battery (C875704300L)
This is a 3.8V, 3000mAh lithium-polymer battery for the BLU Studio C, D830, and D830U smartphones. It replaces OEM part number C875704300L. Install it when the original cell no longer holds a charge or the phone shuts down unexpectedly under load.
- Studio C / D830 / D830U fit: All three models share the same battery bay dimensions, connector pinout, and BMS handshake protocol — one cell covers the full platform without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the D830 platform. The BMS accepted the cell without fault codes, and the charge IC ramped current correctly through CC and CV phases.
- Fuel gauge recalibration after install: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes into an uncalibrated coulomb counter.
Sudden shutdown at 20–30% on the BLU Studio C after a cell swap
A new lithium-polymer cell has a slightly different voltage-to-capacity curve than the aged cell it replaces. The fuel gauge IC still holds the old curve in memory, so it misreads state-of-charge. When the modem fires a transmission burst or the screen peaks in brightness, the new cell's voltage dips below the BMS cutoff threshold — the phone reads 25% but the actual cell voltage has already sagged below 3.2V under load. One full discharge-charge cycle resets the coulomb counter and fixes the mismatch.
BLU D830 not powering on after the battery sat in storage
Lithium-polymer cells in long storage self-discharge below the BMS protection threshold — typically 2.5V per cell. At that point the BMS locks out all output to prevent damage, and the phone appears completely dead. Connect the phone to a wall charger, not a USB port, and leave it for 20–30 minutes without pressing the power button. The charge IC needs to push a small trickle current past the BMS lockout threshold before normal charging resumes. If the charging indicator appears, the cell has recovered — continue to a full charge before first use.