Tesla RoboStar iQ600 Replacement Battery 14.4V 5200mAh N789-603

Tesla RoboStar iQ600 / iQ500 — 14.4V Li-ion Replacement Battery (N789-603)

This 14.4V, 5200mAh lithium-ion battery replaces part number N789-603 in the Tesla RoboStar iQ600 and iQ500 robotic vacuum cleaners. It powers the drive motors, brush roll, and suction fan through a full cleaning cycle. Capacity is sourced from product data at 74.88Wh.

• RoboStar iQ600 and iQ500 compatibility: Both models run the same 14.4V motor rail and use the same N789-603 cell pack with an identical connector and BMS handshake, so one cell fits both platforms without modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the iQ600 platform. The BMS held steady voltage delivery under sustained suction load and tripped correctly on overcurrent — no false cutoffs under normal carpet operation.
• Dock charging habit for the iQ600: Do not leave the RoboStar on the charging dock continuously between uses. These robotic vacuums cycle trickle charge when docked indefinitely, which compresses cell capacity faster than intermittent charging. Charge to full, then remove from the dock.

Suction dropping before the battery indicator reaches low

The iQ600's BMS monitors pack voltage in real time. When the filter is partially blocked, the suction motor draws above its rated current, which causes the pack voltage to sag earlier than a clean-filter run would. The vacuum's indicator reads state of charge, not motor load — so it can show mid-charge while suction is already weak. Clean or replace the filter first before blaming the battery; a clear airpath keeps motor draw within the range this cell is rated to sustain.

Motor cutting out mid-cycle and then recovering after a few seconds

This is a BMS overcurrent trip, not a dead battery. When the brush roll snags on carpet fibres or debris, the motor stalls momentarily and pulls a current spike well above the BMS threshold. The BMS disconnects the output to protect the cells, then resets after a short cooldown — typically a few seconds. Clear the brush roll of hair and debris, then restart the cycle. If the cutouts repeat on open hard floor with no blockage, check that pack voltage at rest sits above 14.0V before suspecting a cell fault.