CPA HALO X Smartphone Replacement Battery 3.7V 1700mAh

CPA HALO X — 3.7V Li-ion Replacement Battery

This 3.7V, 1700mAh Li-ion battery replaces the original cell in the CPA HALO X smartphone. It restores full power to the handset when the factory cell has degraded past usable capacity. Dimensions are 66.20 × 44.00 × 5.10mm — measure your existing cell before fitting.

• CPA HALO X fit: The HALO X uses a compact removable cell with a low-current BMS tied to the phone's fuel gauge IC. This replacement matches the voltage rail and connector pinout that the HALO X power management circuit expects.
• Bench tested on actual hardware: We cycled this cell through charge and discharge under a controlled load matching the HALO X draw profile. The BMS held cutoff correctly at both ends of the voltage window and did not trip under simulated screen and modem load.
• Fuel gauge recalibration on first use: On first installation, run one full discharge to auto-off, then charge uninterrupted to 100% before use. The HALO X fuel gauge IC calibrates its coulomb counter against the new cell's discharge curve during this first full cycle — skipping it causes erratic percentage readings.

Why the HALO X reports wrong battery percentage after a cell swap

The HALO X stores its battery model — discharge curve, internal resistance baseline, and full-charge capacity — in the fuel gauge IC's non-volatile memory. That data was built around the original cell. When a new cell goes in, the stored curve no longer matches actual cell behaviour, so the reported percentage drifts. One complete discharge-to-auto-off followed by an uninterrupted full charge forces the IC to rebuild its model against the new cell. After that cycle, percentage reporting stabilises.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops sharply under load — modem transmit or screen brightness spikes — faster than the fuel gauge predicts. The phone's protection circuit sees voltage fall below the cutoff threshold and shuts down before the reported percentage reaches zero. The root cause is an uncalibrated discharge curve: the IC expects gradual voltage drop but the new cell has different internal resistance. Run the full recalibration cycle first. If shutdowns continue after two full cycles, check that cell voltage reads above 3.5V under no-load conditions before charging.