About this replacement
BLU Studio 5.0C Series — 3.7V Li-ion Replacement Battery (C775004180L)
This is a 3.7V, 1800mAh Li-ion cell for the BLU Studio 5.0C, Studio 5.0e, Studio 5.0CE, and D536, among other models in this lineup. It replaces the original C775004180L when the existing cell has degraded, swells, or no longer holds a usable charge. Dimensions are 77.48 × 49.90 × 4.20mm — measure your existing cell before ordering if you are unsure which variant you have.
- Studio 5.0 series compatibility: These models share the same 3.7V single-cell architecture, connector pinout, and BMS handshake — which is why one cell part number covers the full D536 family across hardware revisions.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the Studio 5.0C platform. The BMS accepted charge current without fault, and cell voltage held within spec across the full discharge curve under mixed screen-on and modem load.
- Fuel gauge recalibration after swap: On first use after installation, run one full discharge down to auto-shutdown, then charge uninterrupted to 100% before normal use. This gives the fuel gauge IC a complete discharge curve to map against the new cell — skipping this step causes erratic percentage readings for days.
Why the Studio 5.0C reports wrong battery percentage after a cell swap
The fuel gauge IC on the Studio 5.0C uses a coulomb counter calibrated to the original cell's discharge curve. When a new cell goes in, that learned curve no longer matches the actual cell chemistry, so the reported percentage drifts from reality — often reading 50% when the cell is nearly flat. The IC needs one complete discharge-charge reference cycle to remap its internal model against the new cell. Until that cycle completes, the OS is essentially interpolating against stale data. After the first full cycle, percentage accuracy typically stabilises within a few points of actual state of charge.
Sudden shutdown at 20–30% on the new cell
This is a voltage cliff issue, not a capacity problem. Under high-current load — active data connection, screen at full brightness, or a background sync burst — cell voltage drops sharply below the BMS cutoff threshold even though the fuel gauge still shows charge remaining. A fresh cell with an uncalibrated fuel gauge IC makes this worse because the percentage readout lags behind the real voltage drop. Charge the phone fully, then run a single uninterrupted discharge cycle to let the coulomb counter anchor to the new cell's actual voltage floor. If shutdowns persist below 3.0V under load, the BMS cutoff is doing its job — check that the cell connector is fully seated.