About this replacement
BlackView A8 — 3.8V Li-Polymer Replacement Battery (A8)
This 3.8V, 1700mAh Li-Polymer cell is a direct replacement for the BlackView A8 smartphone. It powers the phone's processor, display, and cellular radio. Capacity is 6.46Wh, matching the original battery specification.
- BlackView A8 fitment: The A8 uses a fixed 3.8V Li-Polymer architecture with a specific connector orientation and BMS handshake tied to the phone's charge IC. This cell matches that voltage rail and physical footprint — 77.00 × 59.28 × 3.30mm — so it seats correctly in the battery bay without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the A8 platform. The BMS accepted the charge IC handshake on the first cycle, voltage held stable through screen-on and cellular transmission loads, and the protection circuit tripped correctly at low-voltage cutoff.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell. Skipping this step is the main cause of erratic percentage readings after a swap.
Sudden shutdown at 20–30% on the replacement cell
This is a voltage cliff issue, not a capacity fault. Under modem or display load, cell voltage drops faster than the fuel gauge predicts — the phone shuts off before the reported percentage reaches zero. The fuel gauge IC is still calibrated to the old cell's discharge curve. Run one full discharge-charge cycle without fast charging and the shutdowns stop. After that cycle, the coulomb counter resets to the new cell's actual curve.
Device not powering on after sitting in storage
Li-Polymer cells self-discharge in storage. If the A8 has been sitting unused — or the replacement cell shipped at low charge — the BMS may have locked out below the 2.5V per-cell threshold. Plug into a charger and leave it connected for 15–20 minutes before attempting to power on. If the phone remains unresponsive, check that the charger is delivering at least 5V at the USB port, as a low-output adapter may not provide enough current to wake the BMS from lockout.