Flyco FC9601 Replacement Battery 14.8V 2600mAh Li-ion

Flyco FC9601 / FC9602 — 14.8V Li-ion Replacement Battery

This is a 14.8V, 2600mAh (38.48Wh) Li-ion replacement battery for the Flyco FC9601, FC9602, and FC9601 Robot Vacuum cordless vacuums. It slots into the original battery bay and connects to the same BMS handshake as the factory cell. When the original cell loses capacity or stops holding charge, this restores full motor voltage to the suction system.

• FC9601, FC9602, and FC9601 Robot Vacuum compatibility: All three models run the same 14.8V four-cell Li-ion pack with an identical connector and BMS communication protocol. One battery covers the full range without adapter or modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the FC9601 motor board. The BMS correctly reported state of charge, and overcurrent cutoff triggered at the expected threshold under a blocked-filter draw test.
• Dock charging practice for this vacuum: Do not leave the FC9601 sitting on the charging dock permanently. Cordless vacuums on continuous dock charge develop capacity fade significantly faster than those charged only when depleted. Charge to full, then remove from the dock.

Suction dropping before the battery indicator reaches low

This is a voltage sag issue, not always a low-capacity issue. When the FC9601 motor draws sustained current through a partially blocked filter or a dense carpet pass, cell voltage dips under load even if the state-of-charge indicator still reads mid-range. The BMS reads terminal voltage, not actual charge remaining, so the indicator lags behind real available power. Clean the filter first — if sag continues on a clear filter with a new cell, the motor brushes are the next check.

Motor cuts out mid-clean then recovers after a few seconds

This is a BMS overcurrent trip, not a flat battery. When suction is restricted — blocked filter, full dustbin, or hair wrapped around the brush roll — motor current spikes above the BMS cutoff threshold and the pack shuts output to protect the cells. The BMS resets automatically after a short thermal recovery window, which is why the vacuum restarts a few seconds later. Clear the blockage before the next run. If trips continue on an unblocked machine, check that the dustbin seal seats fully, as a partial seal forces the motor to work harder to maintain airflow.