CPA HALO 11 Replacement Battery 3.7V 1300mAh Li-ion

CPA HALO 11 — 3.7V Li-ion Replacement Battery

This is a 3.7V 1300mAh Li-ion replacement battery for the CPA HALO 11 smartphone. It slots into the original battery bay and restores normal charging and standby operation. Capacity is 4.81Wh, matching the factory specification for this handset.

• HALO 11 battery bay fit: The cell measures 60.00 × 43.80 × 4.50mm — the same footprint as the factory unit. The connector orientation and BMS pin-out match what the HALO 11 charge IC expects, so the handset recognises the cell immediately on boot.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the bench. The BMS held the charge cutoff at the correct upper voltage and tripped the low-voltage cutoff before the cell dropped into damaging territory. No thermal flags during the charge phase.
• Fuel gauge recalibration on first use: After fitting this cell, disable fast charging and run one complete discharge-to-charge cycle at standard rate. This lets the fuel gauge IC map the new discharge curve before high-current charging pushes current into an uncalibrated cell, which is what causes erratic percentage readings on first use.

Sudden shutdown at 20–30% on the HALO 11 after a cell swap

A new Li-ion cell has a slightly different voltage-to-capacity curve than the aged cell it replaced. The fuel gauge IC on the HALO 11 still holds the old curve in its coulomb counter. When the phone hits a voltage point the IC associates with near-empty, it cuts power — even if the new cell has capacity left. One full discharge-charge cycle at standard rate rewrites the IC's reference curve. After that cycle, shutdowns at 20–30% typically stop.

Phone warm near the battery compartment during the first charge

A fresh cell arrives with higher internal impedance than a broken-in one. During the first charge, the charge IC pushes current into a cell with more resistance than it expects, which produces more heat than usual at the battery contact area. This is normal and typically settles after the first two cycles as impedance drops. If the phone stays warm beyond the second full charge, check that nothing is blocking airflow around the back cover and that ambient temperature is below 35°C before charging.