Gardena R40 18.5V Replacement Battery 586 57 62-02

Gardena R40 / R80 Series — 18.5V Li-ion Replacement Battery (586 57 62-02)

This is an 18.5V 2500mAh Li-ion replacement battery for the Gardena robotic lawn mower range. It fits the R40, R50, R70, and R80 models, plus nine additional variants in the same family. Capacity is 46.25Wh — matching the original pack specification.

• R40–R80 platform compatibility: These models share the same 18.5V battery rail, connector pinout, and BMS handshake protocol. A single cell configuration covers the full range without firmware or hardware modification.
• Bench tested on actual hardware: We ran this pack through the R40 docking and charge cycle. The BMS accepted the charge handshake on first connection, balanced correctly across cells, and held voltage within spec at full load on the blade motor circuit.
• Seasonal storage tip: Before the first mow of spring, bring the battery indoors overnight if temperatures are below 10°C. Cold Li-ion cells develop higher internal resistance, and the blade motor inrush current on a cold pack can trip the BMS before the mower cuts a single row.

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

Li-ion cells self-discharge slowly during storage. Over a full winter, the pack can drop below the minimum acceptance voltage the Gardena charger checks before it starts a charge cycle. The charger reads this as a fault and refuses to initiate. Most packs in this state are not dead — they need a recovery charge at a lower threshold to bring cell voltage back into the acceptance window. If the charger LED cycles between green and red rather than going solid red, that confirms a low-voltage recovery situation rather than a failed cell.

Mower cuts out mid-row then resumes after a short pause

This is the BMS tripping on thermal protection, not a faulty battery. The blade motor draws a sustained high current through thick or wet grass, and cell temperature climbs until the BMS interrupts the circuit. The mower pauses, the pack cools, and the BMS resets automatically. If this happens repeatedly on a single mowing run, allow a five-minute cooldown before resuming and check that the blade is clean — a clogged or dull blade multiplies the current draw significantly.