My Gardena Sileno Life 1250 has been acting very weird lately: it kept moving back and forth as if it was bumping into objects.
Closer inspection showed a lot of play in the wheels, and considering the two year warranty had expired I took it apart to have a closer look. The motor kit assemblies on both sides of the robot mower showed a fair bit of wear and tear, and the bearings inside were completely gone.
Unfortunately there’s no fail-safe way to replace the bearings, as a lot of screws have seized up over time and the parts are press-fit together. Plus there is a fair bit of wear and tear to the plastic part as well, which is part of the seal. Though I could remake that part in CAD, make an SLS part and reuse the O-ring.
4024 hours of mowing caused this much damage, bit on the low side in my opinion. Consider a mowing period from April to October for a lawn sized 1250m2, which is ~8 hours of mowing per day for 7 months: 1680 hours per year (and that is a low estimate). Based on that, half a year after the warranty period expires you can expect the mower to fail.
Replacement costs? A whopping 189 euros per complete motor kit assembly. So replacing a perfectly fine electric motor and gear box, all that for 4 failed bearings. Talk about an incredibly weak spot in the design. And to consider, the exact same motor kit assembly (with same quality bearings) is used in various Gardena robot mowers, ranging from 250m2 to 2000m2.
It’s not been a good year for Gardena products.