Wolf Garten R10Ac Replacement Battery 25.2V 9000mAh

Wolf Garten R10Ac / R50Ac Series — 25.2V Li-ion Replacement Battery

This is a 25.2V 9000mAh (226.8Wh) lithium-ion battery for the Wolf Garten robotic lawn mower range. It fits the R10Ac, R10D, R30Ac, and R50Ac models. These are fully autonomous mowers — the battery powers both the blade motor and the onboard navigation system simultaneously.

• R10Ac, R10D, R30Ac, R50Ac compatibility: These four models share the same 25.2V battery platform and connector format. The BMS handshake protocol and charge termination voltage are consistent across the range, so one pack serves all four.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on robotic mower test equipment. The BMS handled simulated blade motor inrush without tripping, and cell balance stayed within acceptable limits across the full discharge curve.
• Seasonal storage tip: If the mower has sat unused for several months, charge the battery to roughly 50% before returning it to the dock — not 100%. Storing a fully charged Li-ion pack for extended periods accelerates capacity fade in the top cells.

Charger showing fault light after the mower sat unused all winter

Li-ion cells self-discharge slowly over months. If the pack dropped below the charger's minimum acceptance voltage — typically around 18–20V on a 25.2V pack — the charger will refuse to begin a charge cycle and flag a fault. This is a protection circuit response, not a hardware failure. Some Wolf Garten dock chargers have a recovery mode: disconnect the dock from the wall, wait 30 seconds, reconnect, and reinsert the battery. If the cell voltage is not too far gone, the charger will attempt a slow pre-charge pulse to bring the pack back up to acceptance voltage before switching to normal charge mode.

Mower cuts out mid-row on thick or wet grass then resumes on its own

Wet or dense grass increases blade resistance sharply. The motor draws a higher inrush current, and if that current spike exceeds the BMS threshold, the pack shuts the output circuit to protect the cells. The mower stops, the BMS resets after a short thermal or current-recovery window, and the mower resumes as if nothing happened. This is working as intended — but if it happens repeatedly on normal grass, check that the blade is sharp and clean, since a dull or clogged blade draws significantly more current than a clean one at the same load.