MeiZu 15 Lite BA871 Compatible Battery 3.85V 3000mAh

MeiZu 15 Lite / M15 — 3.85V Li-Polymer Replacement Battery (BA871)

The BA871 is a 3.85V, 3000mAh Li-Polymer cell for the MeiZu 15 Lite and M15 smartphones. It replaces the original battery when capacity has faded or the cell no longer holds a stable charge under load. At 11.55Wh, it matches the factory specification from the product data exactly.

• 15 Lite and M15 compatibility: Both models share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The BA871 fits either variant without modification — the cell measures 73.92 × 62.05 × 3.70mm, matching the factory footprint.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the MeiZu 15 Lite platform. The BMS accepted the cell without triggering an over-voltage fault, and the fuel gauge IC began tracking state-of-charge correctly after one full cycle.
• First-cycle fuel gauge recalibration: After fitting this cell, disable fast charging for the first complete discharge-charge cycle. The fuel gauge IC is calibrated to the old cell's discharge curve. Running one full cycle at standard current lets the coulomb counter re-anchor to the new cell before high-current charging begins.

Why the MeiZu 15 Lite reports wrong battery percentage after a cell swap

The MeiZu 15 Lite uses a fuel gauge IC that builds a discharge model from the previous cell's impedance and voltage curve. When a new cell goes in, that model no longer matches reality. The IC may report 40% while the actual cell voltage is already near 3.5V. One full discharge down to automatic cutoff, followed by a full charge to 4.35V, forces the IC to rewrite its reference curve against the new cell.

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

This happens when the modem or display draws a current spike the cell cannot sustain at that state-of-charge. Voltage drops sharply below the BMS cutoff threshold — typically 3.0V — even though the gauge still shows charge remaining. It is a voltage cliff, not a capacity problem. The fix is the same recalibration cycle: drain to cutoff, charge fully to 4.35V, and the gauge will map the cliff correctly on subsequent cycles.