About this replacement
Shark IZ662H / IZ640H Series — 25.2V Li-ion Replacement Battery (XBATR725)
This is a 25.2V 2000mAh lithium-ion replacement battery for the Shark IZ662H, IZ640H, IZ300UK, IZ300UKT, and compatible cordless stick vacuums. It replaces the original XBATR725 pack. Fit the battery to a depleted or failing unit to restore full motor voltage without replacing the vacuum.
- IZ600 and IZ300 series compatibility: These models share the same 25.2V battery rail, XBATR725 connector footprint, and BMS handshake protocol — which is why a single replacement pack covers the full range listed above.
- Bench tested on actual hardware: We ran the XBATR725 replacement through full charge-discharge cycles on an IZ640H unit. The BMS reported cell balance correctly on all cycles and the protection circuit tripped as expected under a simulated overcurrent load, then recovered cleanly.
- Dock charging habit on Shark stick vacuums: Do not leave this vacuum sitting on the charging dock permanently. Shark cordless vacuums on continuous dock contact develop capacity fade faster than units charged only when depleted. Charge to full, then remove from the dock.
Suction dropping before the battery indicator reaches low
The IZ662H motor draws significantly more current when the filter is partially blocked or airflow is restricted. That extra draw pulls the cell voltage down under load faster than the indicator circuit tracks it. The result is reduced suction at 40–50% indicated charge — the battery reads mid-level but the voltage at the motor terminals has already sagged. Clean the filter first, then retest suction under load. If suction recovers, the battery is fine — restricted airflow was the cause.
Motor cutting out mid-clean then recovering after a short pause
This is a BMS overcurrent trip, not a dead battery. When suction is sustained against a blockage or heavily soiled filter, motor current spikes past the protection threshold and the BMS interrupts the circuit. The vacuum restarts after the BMS resets — typically within 15–30 seconds. The fix is not a new battery. Clear any blockage, clean the filter, and confirm the voltage reads above 22V on a full charge before assuming the pack is faulty.