ZIKOM Z650 Replacement Battery 3.7V 1000mAh Li-ion

ZIKOM Z650 / Z660 / Z710 — 3.7V Li-ion Replacement Battery

This is a 3.7V 1000mAh Li-ion cell for the ZIKOM Z650, Z660, and Z710 smartphones. All three models share the same battery bay dimensions (53.00 × 33.90 × 5.70mm) and voltage rail, so one cell covers the full set. Capacity is 1000mAh — 3.7Wh — matching the original spec.

• Z650 / Z660 / Z710 fit: These three ZIKOM models use the same physical footprint and 3.7V single-cell architecture. The connector pinout and BMS communication protocol are identical across the trio, so the same replacement cell works without modification in any of them.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench and monitored BMS handshake behaviour. The protection circuit responded correctly to cutoff thresholds at both ends — no thermal events, no unexpected disconnect during load.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging begins pushing current into an uncalibrated state.

Sudden shutdown at 20–30% on the Z650 after a cell swap

The fuel gauge IC on the Z650 stores a learned discharge model from the old cell. A new cell has a slightly different voltage-versus-capacity curve, and the IC can misread where the actual floor is. When the modem fires during a call or the screen peaks in brightness, current draw spikes and voltage drops below the cutoff threshold before the gauge expected it. The phone shuts down even though the reported percentage looks safe. One full discharge-charge cycle at standard rate — not fast charge — forces the coulomb counter to relearn the new cell's curve and eliminates the early cutoff.

Phone not powering on after the battery sat in storage

Li-ion cells self-discharge during storage. If this cell dropped below roughly 2.5V per cell before installation, the BMS may have entered lockout mode to prevent damage — and the phone will show nothing when you press the power button. Connect to a known-good charger and leave it for 15–20 minutes without attempting to power on. The charge IC needs to trickle current into the cell above the BMS recovery threshold, typically around 3.0V, before normal charging and boot can proceed.