Friendly Robotics RK1000 Robomow Replacement Battery 18.5V 6400mAh

Friendly Robotics RK1000 Robomow — 18.5V Li-ion Replacement Battery

This 18.5V 6400mAh (118.4Wh) Li-ion battery fits the Friendly Robotics RK1000 Robomow and 22AKFAFB619 autonomous robotic lawn mowers. It powers the cutting deck motor, drive wheels, and onboard navigation without modification. No OEM part number is available for this model — match by voltage and fit model before ordering.

• RK1000 and 22AKFAFB619 platform fit: Both models run the same 18.5V architecture with identical battery connector pinout and BMS handshake protocol. Swapping between these units requires no adapter or firmware change — the pack communicates directly with the mower's control board.
• Bench tested on actual hardware: We cycled this pack through repeated blade-motor inrush loads simulating thick-grass cutting passes. The BMS held stable across start-up current spikes and correctly triggered thermal cutoff when cell temperature climbed beyond threshold, then reset cleanly after cooldown.
• Seasonal storage tip: Before first use of the season, bring the battery indoors overnight if temperatures are below 10°C. Cold Li-ion cells carry higher internal resistance, and the blade motor's inrush current can trip the BMS on a cold pack before the mower completes a single row.

Charger showing fault after the mower sat in the garage all winter

Li-ion cells self-discharge slowly in storage. If the RK1000 sat unused for several months, the pack voltage may have dropped below the charger's acceptance threshold — typically around 14–15V on an 18.5V pack. The charger reads this as a fault and refuses to initiate a full charge cycle. Some chargers have a recovery or trickle mode; if yours does, engage it for 15–20 minutes to bring cells above the acceptance floor, then switch to normal charge. If the charger has no recovery mode, check cell voltage with a multimeter — individual cells below 2.5V indicate the pack needs replacement, not recovery.

Mower cuts out mid-row then restarts on its own a few minutes later

This is thermal cutoff behaviour, not a battery fault. When the blade motor works hard through thick or wet grass, cell temperature rises quickly at 6400mAh draw rates. The BMS shuts down output to protect the cells, then resets once temperature drops — usually within 5 minutes. The fix is to let the mower rest on a flat, dry surface for that cooldown period before restarting. If cutouts happen repeatedly in normal dry grass, check that the blade isn't dulled or jammed, since a dragging blade draws significantly more current than a clean cut.