BLU R2 Plus Compatible Battery 3.8V 2800mAh Li-ion

BLU R2 Plus / R210ww — 3.8V Li-ion Replacement Battery (C876444300L)

This is a 3.8V, 2800mAh Li-ion replacement battery for the BLU R2 Plus and R210ww smartphones. It uses OEM part number C876444300L and slots directly into the original battery bay. Dimensions are 87.00 × 64.00 × 4.40mm — verify these against your existing cell before ordering.

• R2 Plus and R210ww compatibility: Both models share the same battery footprint, connector pinout, and 3.8V nominal voltage rail. The BMS handshake requirements are identical across the two variants, so one cell covers both.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the R2 Plus platform. The BMS accepted the cell without fault flags, and the charge IC held the expected 4.35V upper cutoff throughout testing.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one full discharge-charge cycle at standard rate. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage-cliff problem, not a capacity problem. Budget smartphone cells often have a steeper discharge curve than what the fuel gauge IC was originally calibrated to. When the modem transmits or the screen peaks in brightness, current draw spikes and cell voltage drops below the BMS cutoff threshold — even though the reported percentage still looks healthy. One full discharge-charge cycle at standard rate lets the coulomb counter re-anchor its zero point to the new cell, and the early shutdowns typically stop after that first calibration pass.

Phone warm near the battery during the first charge after swap

A new cell arrives with higher internal impedance than a broken-in cell. The charge IC pushes current into that higher impedance and the energy dissipated as heat is greater on cycle one. This is normal behaviour and not a sign of a faulty cell. Keep the phone out of a case for the first full charge so heat can dissipate. If warmth persists beyond the second full charge cycle, check that the battery connector is fully seated — a partially connected cell forces the IC to work harder to maintain current flow.