About this replacement
BLU Studio Selfie / S070Q — 3.7V Li-ion Replacement Battery (C755005200L)
This is a 3.7V, 1500mAh Li-ion cell that replaces the original battery in the BLU Studio Selfie and S070Q smartphones. It fits the existing battery bay without modification and connects via the stock flex connector. Capacity is rated at 5.55Wh — matching the factory cell spec.
- Studio Selfie and S070Q compatibility: Both the Studio Selfie and S070Q share the same battery bay geometry, connector pinout, and BMS handshake protocol — one cell covers both models. The 75.00 × 50.00 × 4.30mm footprint seats flush with no pressure on the mid-frame.
- Bench tested on actual hardware: We cycled this cell through full charge and load discharge on the S070Q platform. The BMS accepted charge without fault flags, held voltage above 3.5V through mid-discharge, and the protection circuit tripped cleanly at the low-voltage cutoff threshold.
- Fuel gauge recalibration on first cycle: After installation, run one complete discharge to auto-shutoff followed by a full uninterrupted charge before normal use. The BLU fuel gauge IC is calibrated to the original cell's discharge curve — one full cycle rewrites the reference and stops erratic percentage readings from the first day.
Why the Studio Selfie reports wrong battery percentage after a cell swap
The fuel gauge IC on the S070Q uses a coulomb counter referenced against the original cell's internal resistance and discharge curve. When a new cell goes in, that reference is stale. The IC can read 40% while the actual cell voltage is already near the low-voltage cutoff. This mismatch causes sudden shutdowns at percentages that look safe. One full discharge-to-shutoff cycle followed by a complete charge resets the coulomb counter baseline and aligns reported percentage with real cell state.
Sudden shutdown at 20–30% on the replacement cell
This happens when the modem or display draws a short current spike and the cell voltage sags below the BMS cutoff threshold — even though the gauge still shows charge remaining. A fresh Li-ion cell with an uncalibrated fuel gauge IC is especially prone to this in the first few cycles. The fix is not a hardware fault — run the phone through two full discharge and charge cycles without interruption. After calibration, the gauge tracks real voltage more accurately and the shutdowns stop.