About this replacement
BQ Strike Power — 3.85V Li-Polymer Replacement Battery (5514G)
This is a 3.85V, 5000mAh Li-Polymer battery built to the 5514G specification for the BQ Strike Power smartphone. It replaces the original cell when capacity has degraded or the battery is physically damaged. Dimensions are 78.50 × 58.80 × 6.00mm — confirm clearance before installation.
- Strike Power cell compatibility: The Strike Power uses a single Li-Polymer cell at 3.85V nominal. The 5514G connector and BMS handshake are specific to this platform — voltage rail and pin layout match the original charge IC without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a Strike Power unit. The BMS accepted the new cell on the first cycle, charge IC engaged correctly, and protection circuits — overvoltage, undervoltage, and short-circuit — all triggered at expected thresholds.
- Fuel gauge recalibration after swap: On first use after installation, disable fast charging and run one full discharge-to-charge cycle at standard current. This lets the fuel gauge IC map its coulomb counter against 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
A new Li-Polymer cell has a steeper voltage-drop curve than a worn original cell. The fuel gauge IC was calibrated to the old cell's curve, so it misreads remaining capacity. Under modem or screen load, the cell voltage drops sharply below the shutdown threshold before the OS registers low battery. One full discharge cycle — letting the phone reach automatic shutdown, then charging uninterrupted to 100% — allows the coulomb counter to recalibrate. After two to three cycles, the reported percentage and actual cell voltage will align.
Phone not powering on after the replacement cell sat in storage
Li-Polymer cells self-discharge in storage. If the cell voltage dropped below approximately 2.5V, the BMS enters lockout to prevent damage — the phone will show no response to the power button or charger. Connect the phone to a wall adapter, not a PC port, and leave it for 20–30 minutes without pressing anything. The charge IC will trickle current into the cell at a safe rate until voltage rises above the BMS recovery threshold, typically around 2.9–3.0V, at which point normal charging resumes.