McCulloch ROB R600 18V Replacement Battery 2500mAh

McCulloch ROB R600 / ROB R800 Series — 18V Li-ion Replacement Battery

This 18V 2500mAh (45Wh) lithium-ion battery fits the McCulloch ROB R600 and ROB R800 robotic lawn mower series, covering 2017 through to later model years. It slots into the mower's battery bay and connects to the onboard BMS via the original charge and discharge terminals. Voltage and capacity match the factory specification exactly.

• ROB R600 and ROB R800 compatibility: Both mower families share the same 18V battery platform, connector pinout, and BMS handshake protocol. The cell pack geometry — 71.70 x 67.40 x 56.25mm — is identical across the covered model years, so the same unit fits all listed variants without modification.
• Bench tested on actual hardware: We ran this pack through full charge and discharge cycles on the ROB platform and monitored the BMS communication. The protection circuit responded correctly to overcurrent, overtemperature, and low-voltage cutoff events across all test loads — including simulated blade motor inrush.
• Seasonal storage tip: Before storing the mower over winter, charge the pack to around 50–60% rather than full. A fully charged Li-ion cell held at high state of charge for several months accelerates capacity fade faster than a cell stored at mid-charge.

Charger showing a fault light after the mower sat unused all winter

Robotic mower batteries left in storage without a top-up charge can self-discharge below the charger's acceptance threshold — typically around 10–12V for an 18V Li-ion pack. When voltage drops that low, the charger's input detection circuit reads the pack as faulty and refuses to begin a charge cycle. The fix is to apply a brief trickle charge using a compatible Li-ion recovery charger set to the lowest current available, which nudges cell voltage back above the acceptance floor. Once the pack reads above approximately 12.5V, the standard McCulloch dock will accept it and resume normal charging.

Mower cuts out mid-row on thick or wet grass then restarts after a short pause

The blade motor draws significantly more current through dense or wet grass than on dry, short turf — and the pack's BMS has a peak current threshold that triggers a protective cutoff when that inrush exceeds its limit. The mower appears to stall or stop mid-run, then recovers once the BMS resets after a brief cooldown. This is not a faulty battery — it is the protection circuit doing its job. If it trips frequently, lower the mowing height by one step so the blade motor works against less resistance on each pass.