About this replacement
BLU Studio 5.0K / D530K / D531K — 3.7V Li-ion Replacement Battery (C746043210T)
This 3.7V, 1800mAh Li-ion cell replaces the original battery in the BLU Studio 5.0K, D530K, and D531K smartphones. It matches OEM dimensions at 74.15 × 60.00 × 4.08mm, so it seats correctly in the battery bay without modification. Capacity is 6.66Wh — identical to factory spec.
- Studio 5.0K / D530K / D531K compatibility: All three models share the same battery bay geometry, connector pin-out, and BMS handshake protocol. One cell covers all three variants without adapter or re-wiring.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on the D531K. The BMS accepted the charge handshake on the first connection, and protection circuitry tripped correctly at both high-current draw and low-voltage floor.
- Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This gives the fuel gauge IC a clean reference curve against the new cell before high-current charging begins on an uncalibrated coulomb counter.
Sudden shutdown at 20–30% on the Studio 5.0K after a cell swap
A fresh Li-ion cell has a steeper voltage discharge curve than a worn original. The fuel gauge IC on the Studio 5.0K was calibrated to the old cell's curve, so it misreads remaining capacity on the new cell. When the modem fires up for a call or the screen brightness spikes, current draw pulls the cell voltage below the BMS cutoff threshold — even though the OS still shows 20–30%. One full discharge-to-charge cycle lets the coulomb counter reset its internal model against the actual cell curve. After that cycle, shutdowns at falsely reported percentages stop.
Phone feels warm near the battery during the first few charges
A new Li-ion cell typically has higher internal impedance than a broken-in cell. The charge IC pushes current into higher resistance, generating more heat until the cell completes its first few formation cycles. This is normal for the first two to three charges and resolves as impedance drops. If the phone stays warm beyond the third full charge, check that no background process is keeping the screen and modem active simultaneously during charging — those two loads together can keep the charge IC working harder than it needs to.