ZIKOM Z650 Smartphone Replacement Battery 3.7V 1050mAh

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

This is a 3.7V, 1050mAh (3.89Wh) lithium-ion cell built to replace the original battery in ZIKOM smartphones using part numbers Z650, Z660, or Z710. It fits devices where the original cell has degraded or failed completely. Dimensions are 53.00 × 33.90 × 5.60mm — measure your existing cell before ordering.

• Z650 / Z660 / Z710 platform fit: These three part numbers share a common cell footprint and connector pinout across the ZIKOM smartphone range that uses this form factor. Voltage rail and BMS handshake are consistent across all three, which is why a single replacement cell covers all of them.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench with a Z650-compatible unit. The BMS accepted charge without triggering overvoltage cutoff, and the protection circuit responded correctly at the low-voltage threshold before cell damage could occur.
• First-cycle calibration tip: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging pushes power into an uncalibrated cell, which can cause erratic percentage readings early on.

Why the phone reports wrong battery percentage after a cell swap

The fuel gauge IC on ZIKOM smartphones uses a coulomb counter that was calibrated against the old cell's discharge curve. When a new cell goes in, the stored curve no longer matches the actual voltage-to-capacity relationship of the fresh cell. This causes the OS to report inflated or deflated percentages until the IC relearns. Run one complete discharge down to automatic shutdown, then charge to 100% without interruption — the gauge recalibrates during that full cycle.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops sharply under load — typically during a modem transmission burst or screen-on peak draw — and hits the BMS low-voltage cutoff before the gauge shows 0%. The fuel gauge IC reads average voltage, not instantaneous sag, so the percentage looks healthy right until the shutdown. After the first full calibration cycle, the gauge tracks the sag pattern better and the shutdowns typically stop. If they continue past two full cycles, check that the cell connector is fully seated — a loose contact increases resistance and worsens voltage sag under load.