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You have to set limits to robotic lawnmowers, in the past by cable, today by radio
Photo: Matthias Kremp / DER SPIEGEL
There used to be wire, where green grasses sprout today. This is how you could summarize what distinguishes the new generation of robotic lawnmowers from their predecessors. In fact, most devices of this kind have so far had to be limited with a long wire loop. The usually green cable is called a boundary wire according to its function, because that is exactly its job: to limit the mower's leeway. For sensors in the mower, the current-carrying cable is like a wall: this far and no further.
The principle has worked well for years, but it has its quirks: Laying the wire can be a sweaty affair, especially in large gardens. It must be anchored with hooks at short intervals and well planned. If you notice too late that the mower does not find a corner that is too sharp in one place or constantly ends up in the flower bed, you either have to pull the cable out of the ground and lay it again, or patch up additional cable with special connectors.
In addition, the tens of meters of strings can be damaged, for example if someone accidentally cuts them with a spade or if they are damaged by environmental influences. Finding the defective spot in the hundreds of meters long cable can turn into a nerve-wracking search game.
Less cables, more money
A new generation of robotic lawnmowers is now intended to remove this entry hurdle for lawn care by making the devices independent of buried cables. The limits of the modernized models are now set by an app, and depending on the manufacturer, they use different combinations of GPS receivers, sensors and radio technologies for navigation. We brought three such devices into our gardens for testing and checked whether the new technology is really better, what hurdles it entails and, above all, whether the substantial surcharge for the cordless robotic lawnmowers is worth it.
The tested devices at a glance:
Segway Navimow H800E (1749 euros)Satellite navigation is supposed to guide the robotic lawnmower through the garden, a camera (300 euros surcharge)
let it slow down in front of small obstacles.Ecoflow Blade (3000 euros)With the look of a robot fighting dog and elaborate navigation technology, it mows, with an optional leaf sweeping set (800 euros surcharge)
it sweeps the lawn.Ecovacs Goat G1 (1600 euros)
The cheapest model in the test has at least two radio barges with ultra-wideband instead of satellites. Winding gardens require more masts (100 euros surcharge each).
Here's how we tested:
Furnishings: How quickly and easily is it possible to teach the robotic lawnmowers the limits of the working area without a sensor cable?
Service: Is the app control as convenient as you can expect for so much money? In addition to Wi-Fi, is there also mobile radio on board for remote access?
Mowing capacity: How well do the robots find their way around the work surface? How thoroughly do they trim the lawn on the surface and on the edge?
Obstacle detection: Do the pruning tools inadvertently maltreat flora, fauna and garden furnishings or do they avoid them in time with the help of distance sensors?
Segway Navimow H800E
The hope that the base station of the Navimow could be placed freely in the garden destroys the light indicator on the antenna during the test. Their red glowing light says clearly: it doesn't work here. So we pierce the metal post on which a satellite receiver is enthroned, sometimes here, sometimes there, into the ground until the lamp finally turns into a friendly green. Far enough away from the house and tool shed, just not under a tree and certainly not on uneven terrain: such a place is not easy to find in the patchwork garden chosen for the test. That's the price of not having to lay a string.
After the charging station and antenna are fixed and supplied with power, you have to show the mower where to go, literally. With the smartphone app as a remote control, you can drive the boundaries of the lawn, just like with a toy racing car. It's fun, but it requires concentration. A supplied cardboard spacer, which is glued to the robot, is supposed to help maintain a consistent decency towards the edge of the lawn and obstacles. After the first use, however, it is no longer usable because it bends when it touches obstacles. In addition, the supplied adhesive pad quickly detaches from the cardboard and only gets stuck on the robot.
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Display of mowing progress in the Navimow app
Photo: Matthias Kremp / DER SPIEGEL
A spacer made of a more durable material would make more sense, especially since you could use it later. For example, if you want to change the boundaries of the mowing area afterwards or set up protected areas. The latter is useful, for example, to protect the children's paddling pool or a wildflower area from the mower.
The app with which you do all this is basically well done, allows, among other things, the adjustment of the cutting height and the switching off of the annoying sound effects with which the mower otherwise regularly makes itself felt. We found it annoying that the app forcibly played the tutorial video before each change in the garden boundaries until we could speak it along.
In addition to the WLAN, the test Navimow has a built-in LTE module. For example, it can be reached via mobile communications in gardens with inadequate Wi-Fi coverage. The service is free for one year, and up to three years for larger models. Afterwards you have to conclude a contract for this. The manufacturer has not yet provided any concrete information on its costs.
Once everything is set up and the boundaries of the lawn are stored in the mower, the Navimow can get started. In doing so, he proceeds conscientiously like a sports field attendant, driving along the lawn in parallel tracks, quite unlike many other devices that seem to wander across the meadow in a chaotic-looking zigzag. On the one hand, this means that he finishes faster because he knows exactly where he has already cut. On the other hand, you can check the mowing progress at any time via app. Initially, this method ensured that the lanes he had drawn were clearly visible in the lawn, like on a football field. However, since the Navimow realigns its route with each start, this effect quickly disappeared.
In practice, it was shown that the mower came closer to the edges of the lawn than many other robots due to its laterally offset cutting unit. This means that less manual recutting is required at the edges. In the test garden, the Navimow also mastered gradients of 20° and did not try to exceed its digitally set limits. However, in a remote corner of the property, he occasionally complained about having lost contact with the satellite receiver.
While he usually drove around trees, chairs and the like well, the mower's sensors failed with a wooden ball about the size of a tennis ball, which we put in his way as a dummy small animal. For a hedgehog, this could have ended badly. This was a disappointing result, as our test device was equipped with the optical »Vision Fence« sensor – surcharge 300 euros. With the help of artificial intelligence, it is intended to help navigate and detect obstacles.
Ecoflow Blade
So far, Ecoflow has made a name for itself primarily with its power stations, and robotic lawnmowers are new to the company. The debut takes unusual paths, both visually and functionally. Instead of a cuddly mini bumper car, the Blade looks like a martial robot dog with its large wheels equipped with long spikes. Instead of just shortening the lawn, he can also clear it of leaves with a motorized sweeper trailer – for an additional 800 euros.
Before we let the electric mower off the chain, we first have to tame it laboriously. Installing the necessary firmware updates and setting the separate satellite antenna to reception only succeeds after several attempts. Installing the sweeping kit is a fiddly affair because there is little space in the rear of the robot to connect the necessary power cable.
At least the most important setup step works right away. With the app's virtual joystick, we quickly guide the robotic lawnmower along the boundaries of the work area so that it memorizes them. We also create exclusion zones, such as a tree bordered with stones, for safety. Because of the high driving speed, the joystick navigation requires a sure instinct. The jagged edges of the digital map that we create in this way do not interfere later. But you shouldn't be too sloppy either, because the floor plan cannot be changed afterwards, but can only be completely recreated.
The ease of use of the app is otherwise high, many setting options, circuit diagrams and a live map are part of the scope. This is a good thing, because the rubber buttons on the robot housing offer far fewer functions and react spongy. Practical: In addition to Bluetooth and Wi-Fi, the Blade also receives smartphone signals via LTE. In this way, he can be reached when the home network is weakening and can be tracked if thieves kidnap him. A data plan is included for twelve months. At what cost it will continue after that, Ecoflow leaves open.
The wireless navigation works flawlessly. The vehicle always remains in the work area, never mows the beds next to it. On the flat surface, its cutting pattern is convincing. Because the Blade runs everything systematically and its turning circle is small due to the slanted front wheels, practically nothing escapes it. Things don't go so well on the edges. Due to the large distance between the wheels and the mower, the blades do not get close enough. A strip ten to 15 centimeters wide is left standing.
The Blade basically does its job as a leaf collector confidently. He collects almost all of the leaves we distribute. Unfortunately, a lot of grass clippings end up in the collection container, which is quickly full. In order to defoliate the 30 square meter test area, we have to empty the cloth bag three times. Thus, the Blade does not do justice to the concept of autonomous operation in this mode as it does when mowing.
If the heavy team, which is unusually fast at maximum speed, rushes through the garden, it can be intimidating. Fortunately, its combination of laser sensors and a color camera detects obstacles flawlessly. In front of people, trees, garden furnishings and dummy hedgehogs, the Ecoflow Blade brakes in time and swerves. Very few robotic lawnmowers are that attentive at the moment.
Ecovacs Goat G1
The manufacturer, known for robot vacuums, named its first mower very down-to-earth after goats. The look of the device, on the other hand, is so spacey that we can also imagine the vehicle as a cutting aid for a Martian colony. However, the white case does not remain chic for long without cleaning hands. The large base station cleans the upper of the two camera eyes with a windshield wiper, nothing else.
Apart from the hassle of balancing the bulky components in place, the setup is not difficult. The good instructions in the app help to install signal poles in the right places on the lawn boundaries. Together with a stub antenna on the robot housing, they form an ultra-wideband radio network (UWB) that guides the vehicle across the work surface. Two transmission masts, each with three mono cells as power supply, are included in the scope of delivery. Large or intricately shaped base thicknesses require additional transmission masts, unit price 100 euros.
Before the Goat G1 can graze its territory without supervision, we show it the limits via app. The mower responds well to the virtual joystick. Therefore, the layout of the mowing area is quickly laid out. However, it cannot be subsequently adapted. If you want to redesign the lawn, a completely new round of getting to know each other is necessary.
There is nothing else wrong with the app. The range of functions and overview are right – just like with Ecovacs' robot vacuums, which can be controlled with the same software. Out of the box, the Goat G1 responds to Bluetooth and Wi-Fi signals. Optionally, you can retrofit a mobile radio module for 250 euros, the price of which includes three years of data usage. For 100 euros you get such a module, in which you can insert your own SIM card. With both variants, the location of the mower as well as almost all functions can also be controlled remotely.
Only the cutting height cannot be adjusted by software, but only on the robot housing. There is also a display and several buttons. Therefore, the Goat G1 can also be operated without a smartphone.
After manual preparatory work, the Ecovacs mower ensures largely autonomous lawn care. The cutting pattern is very uniform in the surface. Only the edges remain messy because the robot doesn't get very close to them to be on the safe side. However, it is not a good idea to fall below the buffer of ten centimetres to the edge recommended by Ecovacs. Because we first dare to do this when mapping, the mower initially slips into the bed from time to time. This does not happen with a floor plan that is then recreated with a prescribed distance. Trimming the edges of the lawn, however, leaves the Ecovacs device hanging on us.
Properly adjusted, the electric goat navigates flawlessly across the garden area without leaving out areas or straying from the path. But the robot has to avoid obstacles even better. So far, this has only worked reliably if they are more than ten centimeters high. Smaller hedgehog dummies are partially overlooked by the camera duo trained with artificial intelligence. Then the robot rumbles over it humorlessly. With a firmware update, Ecovacs could get rid of such misbehavior on the Goat G1. Such a tutoring has also worked with the Ecoflow Blade.
Result
A buried sensor cable that navigates the mowers through the garden? We don't miss that one bit in the test. It is much more convenient to teach the robots the floor plan via app joystick. All three test models find their way around the pitch well via radio control. The signal masts of the Ecovacs Goat G1 have enough reception right away. Aligning the satellite antennas of Segway and Ecoflow correctly takes longer and is annoying. But even that still takes less trouble than burying a cable.
The app operation is convenient in all three cases. The Segway software scores with the fact that you can adjust the lawn floor plan at a later date. The other devices have to be completely retaught.
When it comes to mowing performance, the trio doesn't take anything away. They shorten the large area thoroughly and without gaps. But they always leave a strip on the edge – the Segway mower a little less than the other two. The Ecoflow Blade is the only device that can also collect leaves. The fact that the quickly filled collection container often has to be emptied by hand reduces the gain in comfort compared to manual work.
Unlike many conventional robotic lawnmowers, these three models have additional distance sensors on board. They can detect large obstacles such as garden furniture and equipment, favorite plants and even human limbs from a distance and usually avoid them without touching them. For small animal welfare, we currently only consider the Blade to be fully suitable. Segways and Ecovacs' sensors ignore hedgehog-sized dummies too often in the test. However, manufacturers can improve this by updating the software.
This result does not allow for a clear winner. Instead, the choice of the most suitable device may be determined by the respective specialty: Ecovacs are the fastest way to get started, Segway offers the most flexible lawn design and the best edge cut, and the Ecoflow has the most tender collision protection despite its grim exterior.
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