TCL A860 Replacement Battery 3.7V 1500mAh Li-ion

TCL A860 / A998 / W989 Series — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1500mAh Li-ion cell that replaces the original battery in the TCL A860, A998, W989, and A968 smartphones. These are compact feature-tier handsets where the original cell commonly degrades after 18–24 months of regular use. Capacity is rated at 5.55Wh, matching the original cell specification.

• A860 / A998 / W989 / A968 compatibility: These models share the same battery bay dimensions (64.60 × 43.95 × 5.10mm), voltage rail, and connector pinout. The charge IC on each device accepts the same BMS handshake, so no firmware mismatch occurs on first boot.
• Bench tested on actual hardware: We cycled this cell through charge and load on compatible hardware. The BMS held cutoff correctly at both ends — no overcharge trip above 4.2V and no low-voltage lockout during normal draw. Voltage at full charge measured stable at 4.18–4.20V.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map its charge curve against the new cell before high-current charging begins on an uncalibrated coulomb counter.

Sudden shutdown at 20–30% on a replacement cell

This is a voltage cliff problem, not a capacity problem. Under modem TX bursts or screen brightness spikes, the cell voltage drops sharply if the fuel gauge IC is still calibrated to the old cell's discharge curve. The phone's low-voltage protection trips before the percentage readout catches up. One full discharge-to-shutdown followed by an uninterrupted charge to 100% resets the coulomb counter and eliminates most cliff shutdowns.

Phone shows wrong battery percentage after cell swap

The fuel gauge IC stores a learned discharge curve from the old cell. After a replacement, that stored curve no longer matches actual cell chemistry, so the percentage readout drifts — often reading 15–20% high or dropping suddenly near 40%. The fix is one full cycle: drain the phone until it shuts off on its own, then charge uninterrupted to 100% without removing the charger early. After that cycle, the IC rebuilds its curve against the new cell and percentage accuracy stabilises.