Charging stops part-way, around 40 to 75%: LUBA 2, YUKA and YUKA mini 2

What owners report

• A YUKA 2000 on 1.30.29.26 stopped charging at 50% for three days running. The mower then never finished its task, because it kept waiting for a full charge. The LUBA 2 owner in the next item replied that theirs does the same¹.
• A LUBA 2 on 1.30.29.26 charged unevenly after the update: it started mowing at 32% after what the owner thinks was a night's charge, and two and a half hours on the charger later read only 52%. The owner says it was fine before the update².
• A LUBA 2 AWD on the same version charged to 73%, then stopped and waited on the dock, neither charging nor mowing².
• A LUBA 2 AWD started charging and stopped after a few minutes, after its owner had cleaned the contacts, levelled the station, re-added the mower in the app and pulled and reinserted the safety key³. A second owner in that thread had the same pattern: a normal charge to about 50 to 55%, then charging that starts and stops every minute or so³.
• A YUKA mini 2 800 has not charged past 63% since a firmware update in mid-August⁴.
• A LUBA 2 bought in 2024 charged to 100% while everything was indoors. After a few days back outside, with the adapter still indoors, charging stopped between 38 and 45% again, although the owner had cleaned the contacts⁷.

The power adapter's batch number

In replies to three of these owners, Mammotion accounts asked for a clear photo of the adapter showing its batch number, and suggested checking it^{2, 3, 7}. One owner says support told them that early adapters have a known issue, that the batch number is stamped on the adapter, and that batch 2432 or earlier is a known bad unit. The LUBA 2 AWD owner above then found batch 2403 on theirs³. The LUBA 2 owner from 2024 found batch 2413 on theirs, had no charging limit set, and says a new charger from the retailer fixed all the issues⁷. The range comes from one owner's account of a support conversation, not from Mammotion in writing. If your adapter is outdoors, the adapter page covers why that matters.

What else was suggested or found

• Mammotion's steps for a YUKA stopping at 50%. A Mammotion account asked for the device name, then to restart the device three times and make sure it is on the latest firmware⁹. It also asked what colour the light on the power adapter shows while charging, and, for an owner who has a multimeter and knows how to use it safely, the voltage at the adapter and at the charging station⁹.
• A dead power supply gave the same symptom. A YUKA owner in that thread says charging stopped at about 50% when their own power supply died¹⁰. The owner of the 50% case replied that it charged correctly from 15% to 50%, which looked odd to them¹.
• A YUKA with two batteries. An owner whose YUKA stopped at 50% with an extra battery installed was told by a Mammotion staff account to try charging with only one battery installed¹¹. The owner says a reboot let it reach 59% with two batteries, and then it quit¹². No outcome had been posted when this was checked.
• A LUBA 3 that died mid-mow. An owner whose LUBA 3 AWD 5000 had started dying on the spot, with a battery that looked healthy until it dropped, was told by one commenter that a new power-brick cord fixed theirs, after a battery swap from tech support had not¹³. Another says Mammotion replaced the charging board on theirs, and that theirs would only ever charge to 36%, which they take to point at the power control circuitry rather than the battery¹⁴. Both are single owners' accounts, not a diagnosis.

What the newest firmware says

On September 27 Mammotion announced 2.3.31.69 for LUBA 3, LUBA mini 2 Series and YUKA mini 2 Series. One line of its notes: "Fixed an issue where charging occasionally failed to reach the set battery level."⁵ That is the line the YUKA mini 2 800 above belongs to. The same post announced 1.30.31.19 for LUBA 2, LUBA 2X, YUKA, LUBA mini Series and YUKA mini Series, and its notes list no charging fix⁵.

Not every partial charge is this

A charging limit can stop a charge part-way by design. LUBA 2 AWD owners describe a battery page in the app, reached from the battery icon or from Settings, then Battery: a custom mode sets the charging upper limit, and a smart mode stops at 80%⁶. A mower that docks crooked, dirty contacts or a stuck pin can also stop a charge part-way, and these are cheaper to rule out. The contact-pin guide and the dealer's charging-station diagnosis cover how to tell them apart, including how to test the adapter with a meter.

A cold battery can stop a charge too. A LUBA 3 owner, whose mower had been stuck out overnight and was carried to the station, found it stuck at 12% with the app saying the limit was reached. Cleaning the contacts and power-cycling the charger and mower did not help, and it started charging again after about an hour. A Mammotion account checked the logs, found alerts that the battery temperature was too low, and wrote that when the battery drops below 6°C the robot may be unable to charge properly. The owner's weather station read just above 6°C, and the ground may have been colder⁸.