BT45A Meizu Meilan Note 2 Compatible Battery 3.8V 2900mAh

MeiZu Meilan Note 2 / M2 Note — 3.8V Li-Polymer Replacement Battery (BT45A)

This is a 3.8V, 2900mAh Li-Polymer replacement cell for the MeiZu Meilan Note 2, covering model variants M571H, M571C, and M2 Note. It slots in place of part number BT45A and restores full charging and discharge function to the phone. Capacity is rated at 11.02Wh and matches the original specification.

• M571H and M571C variant fit: Both M571H and M571C share the same battery bay dimensions, connector pinout, and BMS handshake protocol — that is why one cell covers all listed variants. The 75.90 × 60.16 × 4.20 mm footprint is consistent across the production run.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on M2 Note hardware. The BMS accepted the cell without fault flags, charge termination triggered correctly at 4.35V, and low-voltage cutoff fired at the expected floor without false trips.
• First-cycle fast charge protocol: On first use after installation, disable MeiZu's fast charging mode for one complete discharge-charge cycle. This lets the fuel gauge IC build an accurate discharge curve against the new cell before high-current charging pushes current into an uncalibrated coulomb counter.

Sudden shutdown at 20–30% on the Meilan Note 2 after a cell swap

This is a voltage cliff problem, not a capacity problem. When the modem fires a high-current burst during a call or data session, the new cell's voltage sags below the BMS cutoff threshold before the fuel gauge reads zero. The phone interprets that hard cutoff as a crash rather than a low-battery event. One full uninterrupted discharge-to-cutoff cycle recalibrates the fuel gauge IC against the new cell's actual voltage curve and eliminates most of these shutdowns.

OS reporting 100% charge immediately after plugging in a new BT45A cell

The coulomb counter in the fuel gauge IC still holds state data from the old, degraded cell. When a fresh cell is installed, the IC maps the new cell's resting voltage — typically around 3.75–3.80V out of packaging — against an outdated discharge table, returning an inflated percentage. The fix is one complete discharge to auto-shutoff, then a full uninterrupted charge to 100% with the screen off. After that single cycle the IC resets its reference points and percentage tracking stabilises.