Friendly Robotics RK1000 Replacement Battery 18.5V 3200mAh

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

This 18.5V, 3200mAh (59.2Wh) Li-ion battery replaces the original pack in the Friendly Robotics RK1000 Robomow and the 22AKFAFB619 variant. It powers both the blade motor and the drive system that moves the mower autonomously across the yard. No OEM part number is published for this pack, but the voltage, capacity, and connector match the original specification.

• RK1000 and 22AKFAFB619 compatibility: Both model codes share the same 18.5V battery bay, connector pinout, and BMS handshake protocol. Swapping between them does not require any firmware or hardware change on the mower side.
• Bench tested on actual hardware: We ran this pack through blade-start inrush cycles and monitored BMS response at rated voltage. The protection circuit held within normal trip thresholds across repeated high-draw starts without nuisance cutoff.
• Seasonal storage tip: Before the first mow 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 takes a single cut.

BMS cutoff on thick-grass or wet-grass blade load

The RK1000 blade motor draws significantly more current when cutting dense or wet grass than it does on dry, short turf. If the pack's BMS reads a sustained overcurrent event — common during the first few passes on an overgrown section — it cuts power to protect the cells. This is not a faulty battery; it is the protection circuit doing exactly what it should. Clear the stalled condition, allow a two-minute rest, and restart the mower on a lighter section to reset the BMS latch.

Charger showing a fault light after the mower sat all winter

Li-ion cells self-discharge slowly during storage. If the RK1000 sat in an unheated garage from October to April, the pack voltage may have dropped below the charger's acceptance threshold — typically around 12V for an 18.5V nominal pack. Many chargers refuse to charge a pack below this floor and flash a fault or error light instead. Some chargers include a "wake" or "recovery" mode that applies a trickle current to bring the pack back above the acceptance threshold; check your charger manual for that function and run it before declaring the pack dead.