Coolpad F61 Compatible Battery 3.7V 1000mAh CPLD-42

Coolpad F61 — 3.7V Li-ion Replacement Battery (CPLD-42)

This is a 3.7V, 1000mAh Li-ion cell for the Coolpad F61 smartphone. It replaces OEM part CPLD-42 and fits the F61 directly. Voltage and physical dimensions — 59.67 × 39.66 × 4.26mm — match the original cell specification.

• F61 fit and connector match: The CPLD-42 uses a connector pinout specific to the F61 board layout. The BMS handshake must match the charge IC on that board — swapping a generic 3.7V cell without the correct protection circuit will throw charge faults or refuse to power on entirely.
• Bench tested on actual hardware: We cycled this cell through a full discharge and charge sequence, confirmed the BMS protection tripped correctly at low voltage, and verified charge termination at 4.2V under the F61 charge IC.
• Fuel gauge recalibration on first install: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.

Why the F61 reports wrong battery percentage after a cell swap

The F61 uses a fuel gauge IC that tracks charge state against a learned discharge curve from the old cell. When a new cell goes in, that curve no longer matches. The IC interpolates incorrectly, so the percentage jumps or stalls at values that don't reflect real charge. One full discharge-to-shutdown followed by an uninterrupted charge to 100% forces the IC to relearn the curve against the new cell.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below the modem or display's minimum rail requirement under peak load — even though the gauge reads 20–30% remaining. The old fuel gauge calibration predicts headroom that the new cell doesn't have at that state of charge under load. The BMS cuts output to protect the cell before the gauge catches up. Run two full discharge-charge cycles and the gauge IC will recalibrate; shutdowns at that range should stop once the coulomb counter is tracking the correct voltage cliff.