CPA Halo 5 Fitness Tracker Replacement Battery 3.7V 1200mAh

CPA Halo 5 / Halo 6 / Halo 8 — 3.7V Li-ion 1200mAh Replacement Battery

This 3.7V 1200mAh Li-ion cell replaces the original battery in the CPA Halo 5, Halo 6, and Halo 8 smartphones. It matches OEM voltage and physical dimensions (53.00 × 34.00 × 5.70mm), so the connector and fit are direct. Capacity is 1200mAh (4.44Wh), taken from product specifications — not extrapolated.

• Halo 5, 6, and 8 platform compatibility: These three models share the same battery bay geometry and voltage rail. The BMS handshake expects a 3.7V nominal cell with the same connector pinout — swapping between any of these models uses the identical replacement unit.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the Halo platform. The BMS accepted the cell without protection trips, and charge termination triggered correctly at 4.2V under standard CC/CV protocol.
• Fuel gauge recalibration after swap: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This gives the fuel gauge IC time to map the new cell's discharge curve before the charge IC pushes higher current into an uncalibrated cell.

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

This happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The phone's reported percentage no longer matches actual cell voltage, so the OS thinks there is charge remaining when the cell voltage has already dropped below the load threshold. Under screen-on or network load, the new cell hits its voltage floor before the OS reaches 0%. One full uninterrupted discharge-charge cycle lets the coulomb counter reset against real cell data and eliminates the false shutoff.

CPA Halo showing incorrect battery percentage after replacement

The fuel gauge IC learns cell behaviour over time and stores that data for the original cell. A new cell resets that baseline, so percentage readings jump or plateau at odd values — 60% sitting for two hours, then dropping fast. The fix is to run the battery completely flat until the phone shuts itself off, then charge uninterrupted to 100% without using the device. After that cycle, the gauge IC recalibrates its internal model to the new cell's actual charge curve.