ZIKOM Z650 Compatible Battery 3.7V 1200mAh Li-ion

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

This is a 3.7V, 1200mAh Li-ion cell replacing the original battery in the ZIKOM Z650, Z660, and Z710 smartphones. At 53.00 × 33.90 × 5.70mm, it matches the physical footprint of the factory cell. Swap it in when the original no longer holds a usable charge through a normal day.

• Z650 / Z660 / Z710 shared platform: These three models run the same 3.7V battery rail and use an identical connector pinout and cell cavity, which is why one cell covers all three. The BMS handshake uses the same charge IC across the range.
• Bench tested on actual hardware: We cycled this cell through full charge-discharge passes and monitored BMS cut-in and cut-off thresholds. The protection circuit tripped correctly at low-voltage floor and the charge IC accepted the cell without fault flags on a standard USB input.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard current. This gives the fuel gauge IC a clean discharge curve to map against the new cell before any high-current fast charging runs into an uncalibrated coulomb counter.

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

This is a voltage cliff issue, not a capacity issue. When the modem or screen pulls a high current burst, a fresh cell with an uncalibrated fuel gauge IC can sag below the system cutoff voltage even though the reported percentage still shows charge remaining. The phone interprets the voltage drop as a hard low-battery event and shuts down immediately. Run one full discharge to 0% and a full charge to 100% without interruption — this resets the coulomb counter baseline and the shutdowns stop.

Phone warm near the battery during the first two charges

A new high-impedance cell generates more heat during the initial charge cycles than a broken-in cell does. The charge IC pushes current into a cell with higher internal resistance, and that resistance converts some energy to heat rather than stored charge. This is normal for the first two or three cycles and the temperature drops as the cell's internal resistance settles. If the phone stays warm after the third full charge, check that the back cover is seated flush — poor thermal contact with the chassis traps heat.