Robot lawn mowers are very popular because they take on tedious work and take good care of the lawn. But they also have (security) shortcomings - two institutions have published new test results.
Berlin / Cologne (dpa / tmn) - Robot lawn mowers are supposed to relieve hobby gardeners of a job that is tedious and tiring, so that they have more time for what is fun in the garden. The idea works well - nevertheless, anyone who wants to buy such a device should say goodbye to the idea that the little robot can work independently. He needs help, often even daily - not to become a security risk.
Because the sensors of the devices do not stop them sufficiently with some obstacles and even dummy children. The latter for none of the eleven devices that Stiftung Warentest tested (magazine "test", edition 4/2020). Replicas of children's arms or legs were cut, cut or scratched.
Child can reach under the device and into the knife
In addition, the testers were able to simulate all but one device so that a child playing could reach under the running robot and thus into his knife. The result can be transferred for dogs.
The recently published test by Tüv Rheinland and the magazine "Selbst ist der Mann" (April 2020 edition) came to the same result: eleven of the twelve devices injured a dummy of a child's arm.
Likewise, most robotic lawnmowers do not recognize that objects are still on the green. "My experience with this test showed that you really have to clean up every evening, otherwise broken balls and garden tools will be damaged the next day," reports Peter Baruschke, test editor of "Selbst ist der Mann".
Manufacturers point out the dangers
But it can also put the risk to children in perspective: "All devices comply with the applicable safety standards," says Baruschke. "Unfortunately, there have been isolated accidents with children who were injured on the lawn by a robot lawn mower."
It has therefore already been decided to add two tests to the current standard - which are now also taken into account in current safety assessments. This includes that the devices recognize and drive around a kneeling child's dummy and a replica of a child's arm with a fold-out metal finger - the "child's test arm" - reports Baruschke.
"These tests are already necessary to obtain the GS mark for tested safety," adds the expert. His advice is nevertheless: Consistently tidying up the lawn before the robot starts.
By the way, you have to keep the manufacturers to good use: According to the testers on both sides, the companies point out in the operating instructions that children and pets should be kept away from active robot lawn mowers.
Small devices get stuck in obstacles
The testers have another criticism: Many lawn mowers often need practical help to do their job. Particularly compact robotic lawnmowers and also some of the less expensive devices needed a hand almost every day to free them after a standstill, reports Baruschke.
The devices got stuck on bumps in the lawn or had problems finding the charging station on the way back. The picture was sometimes "miserable", as the test editor describes: The robots sometimes wandered around the lawn edge in an endless loop or drove against a resistance with rotating wheels until the battery went flat. They left lanes in the beautiful lawn.
Lawn robots mow better and better
But there is also good news: Stiftung Warentest and "Selbst ist der Mann" test lawn robots regularly and can confirm better results for the models mentioned above, which of course they had to test last summer for organizational reasons. You navigate largely without problems, and only a few fringed spots remain.
Conclusion of the goods testers: Even the inexpensive devices from 330 euros mow with "good" to "satisfactory" result. And Baruschke emphasizes: "With some manufacturers, there was hardly anything to do: We connected the devices and let them run for a week or two - without any problems."
Lawn robots with perimeter fence make work easier
The robots' desperate drives against insurmountable obstacles can also be managed. It is important that the boundary wire is carefully laid: similar to a pasture fence for cows, this shows the lawn robot its limits at lawn edges or before beds with the help of a slight current flow.
"If necessary, you have to surround slightly protruding roots with it," says Baruschke. This applies in particular to the small devices that are less difficult to drive over obstacles. "Otherwise it is better to use another device: the larger the robot lawn mower, the fewer problems they have."
Then freeing a robot lawn mower from traps will not work out - the time spent on this should not be overestimated. Because the robotic lawn mower should work up to five times a week in summer if you want a densely grown, juicy lawn.
Info box: The test results at a glance:
The test winners of the magazine "test" / Stiftung Warentest, all with a "satisfactory" overall rating: Indego S + 400 from Bosch, Automover 105 from Husqvarna, Robolinho 500E from Al-Ko, RMI 422.0 from Stihl, Easymow 6HD from Power G and ROB S600 from MCCulloch.
The test winners of the magazine "Selbst ist der Mann", all with an overall rating of "good": RMI 422 PC from Stihl, smart Sileno lif from Gardena, Robolinho 500i from Al-Ko, Automower 305 from Husqvarna and P10 Powerworks.