Meizu BA816 V8 Replacement Battery 3.85V 3200mAh

MeiZu V8 / M816Q — 3.85V Li-Polymer Replacement Battery (BA816)

The BA816 is a 3.85V, 3200mAh lithium-polymer cell that fits the MeiZu V8, V8 Dual SIM TD-LTE, and M816Q smartphones. It replaces the original battery when capacity has faded to the point where the phone can no longer hold a useful charge through a normal day. Dimensions are 74.90 × 60.40 × 4.06mm — verify clearance before fitting.

• V8 and M816Q platform compatibility: Both the V8 and M816Q share the BA816 footprint and connector pinout. The BMS handshake uses the same communication line for fuel gauge IC reporting, so the replacement cell integrates with the existing charge controller without modification.
• Bench tested on actual hardware: We cycled the BA816 through charge and discharge on the V8 platform. The BMS held cutoff correctly at the low-voltage threshold and accepted charge current without triggering protection mode on the first cycle.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the BA816 replacement cell

A new lithium-polymer cell has a slightly different discharge curve than the aged cell it replaces. The fuel gauge IC on the V8 is still calibrated to the old curve, so it misreads state of charge. Under modem or display load, the cell voltage drops below the BMS cutoff threshold before the OS registers critical battery level. The phone cuts out because the cell can no longer sustain voltage under that load — not because capacity is low. One full discharge cycle below 5% followed by a complete charge resets the coulomb counter and corrects this behaviour.

MeiZu V8 not powering on after the battery was stored flat

If the BA816 cell dropped below approximately 2.5V during storage, the BMS enters lockout to prevent cell damage. The phone will show no response to the power button and may not register on the charger immediately. Connect the device to a wall adapter — not a PC USB port — and leave it for 15 to 20 minutes before attempting to power on. The charge IC will trickle current into the cell until voltage rises above the BMS re-enable threshold, typically around 2.8V, at which point normal charging resumes.