AL-KO robot mower displays E9 and shuts down unexpectedly during operation.

Safety first: Turn off the mower and disconnect it from the charging station before opening any covers.

• Check charge level: Place the mower in the charging station and allow it to charge until the display shows full or the charging LED indicates completion. Then start a short mowing cycle and observe runtime.
• Inspect battery connector: With power off, open the battery compartment. Check that the battery plug is fully seated and that there are no signs of overheating or corrosion.
• Measure battery voltage: If you have a multimeter and experience, measure the pack voltage and compare it to the nominal voltage printed on the AL-KO battery label. A significantly lower voltage after full charge indicates a failing pack.
• Check station output: Verify that the charging station is supplying the correct voltage at the contacts (refer to service data). If not, the station electronics may be faulty.
• Battery replacement: If the mower runs only a short time before E9 or shuts down, replace the battery with an original AL-KO robot mower battery of the same capacity and chemistry.