About this replacement
BLU C5 / C010Q — 3.7V Li-Polymer Replacement Battery (C775840200L)
This 3.7V, 2500mAh Li-Polymer cell replaces OEM part C775840200L in the BLU C5 and C010Q smartphones. It matches the original pack's voltage rail, physical footprint (76.90 × 58.50 × 4.50mm), and connector orientation. Capacity is rated at 9.25Wh — identical to the factory specification.
- C5 and C010Q platform fit: Both models share the same battery bay dimensions, 3.7V nominal rail, and BMS handshake protocol — one cell covers both variants without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on a BLU C5 unit. The BMS accepted the pack without fault flags, and the charge IC completed the constant-current to constant-voltage transition cleanly at 4.2V.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before the OS starts reporting accurate percentages.
Sudden shutdown at 20–30% on the BLU C5 after a cell swap
This happens because the fuel gauge IC is still using the discharge curve it built around the old, degraded cell. The new cell has a steeper voltage drop under modem and screen load than the IC expects, so it misreads remaining capacity. When the phone pulls current for a data burst or screen wake, voltage dips below the hardware cutoff threshold — around 3.2V — before the gauge catches up. One full discharge-charge cycle at standard current forces the coulomb counter to rebuild its reference curve against the new cell.
BLU C5 won't power on after sitting in storage — BMS lockout recovery
Li-Polymer cells that drop below approximately 2.5V per cell trigger a protective BMS lockout to prevent damage. If the phone shows no response and won't charge via USB, the BMS has likely tripped. Connect the phone to a wall charger — not a PC port — and leave it for 15–20 minutes without pressing any buttons. The charge IC delivers a trickle current that nudges cell voltage above the BMS re-enable threshold, typically 2.9V, at which point normal charging resumes and the phone will power on.