About this replacement
MeiZu Pro 6s / M570Q-S — 3.85V Li-Polymer Replacement Battery (BT53S)
This is a 3.85V, 3050mAh (11.74Wh) Li-Polymer cell built to OEM spec BT53S for the MeiZu Pro 6s and M570Q-S Dual SIM TD-LTE. It replaces a degraded or failed original cell and restores the phone's ability to power calls, apps, and screen-on use at normal voltage levels. Fit is direct — same connector, same form factor at 68.50 × 60.40 × 4.00 mm.
- Pro 6s and M570Q-S compatibility: Both the Pro 6s and M570Q-S share the BT53S battery connector, cell footprint, and BMS handshake. The voltage rail is identical across both variants, so one cell covers the full compatibility range without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge sequences on the Pro 6s platform. The BMS accepted the cell without error flags, charge termination triggered correctly at 4.35V, and protection cutoff engaged at the expected low-voltage threshold.
- First-cycle fast charge protocol: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate its coulomb counter against the new cell's discharge curve before mCHarge pushes high current into an uncalibrated state.
Sudden shutdown at 20–30% on the BT53S replacement cell
This is a voltage cliff issue, not a capacity fault. When the modem transmits or the display brightness spikes, instantaneous current draw pulls the cell voltage below the BMS cutoff threshold — even though the fuel gauge still reads 20–30%. The old cell's internal resistance profile was mapped into the fuel gauge IC; the new cell has a different curve, so the gauge reads optimistically until load collapses voltage. One full slow discharge to shutdown, followed by an uninterrupted charge to 100%, resets the coulomb counter and eliminates most cliff events.
OS reporting wrong battery percentage after cell swap
The fuel gauge IC on the Pro 6s stores a learned discharge model from the previous cell. Swapping to a new BT53S cell doesn't automatically wipe that model, so the OS inherits stale calibration data and displays incorrect percentages — often reading 100% for longer than expected, then dropping sharply. The fix is a full calibration cycle: charge to 100% without interruption, use the phone normally until it shuts down on low voltage, then charge back to 100% in one session. After that cycle, the coulomb counter locks to the new cell's actual capacity curve.