MyPhone BS-02 Halo2 Replacement Battery 3.7V 1200mAh

MyPhone Halo2 — 3.7V Li-ion Replacement Battery (BS-02)

This is a 3.7V, 1200mAh Li-ion replacement battery for the MyPhone Halo2 and Halo 1075 smartphones. It fits the original BS-02 and BS-01 battery slots directly. Use the capacity figure from the product data — 1200mAh — when comparing against your original cell.

• Halo2 / Halo 1075 compatibility: Both the Halo2 and 1075 share the same 3.7V single-cell architecture and BS-series connector pinout. The charge IC on both models expects the same BMS handshake voltage, so one cell fits both without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge under modem-active and screen-on load conditions. The BMS held the cutoff voltage correctly and did not trip under the combined draw of calls and display at full brightness.
• Fuel gauge recalibration on first use: After fitting this cell, disable any fast-charge mode and run one full discharge-charge cycle before normal use. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging begins on an uncalibrated reference.

Sudden shutdown at 20–30% on the Halo2 after a cell swap

The Halo2's fuel gauge IC stores a discharge curve from the old, degraded cell. When a fresh cell is fitted, the IC underestimates how much voltage remains at mid-range state of charge. Under modem or screen load, the phone sees the voltage drop briefly and interprets it as a depleted cell. One full discharge to automatic shutdown — then a full charge without interruption — overwrites the stored curve and stops the early cutoffs.

Battery percentage jumping erratically after replacement

Erratic percentage jumps — 45% dropping to 12% then back to 40% — mean the coulomb counter is recalibrating against a cell it has no reference data for. This is normal in the first one to two cycles on the Halo2 after a cell swap. Run the phone down to zero until it shuts itself off, then charge uninterrupted to 100%. After that cycle the percentage readings stabilise against the new cell's actual capacity.