A great robot for the largest of lawns

Verdict

Powerful, reliable and able to cut lawns brilliantly, the Stihl iMOW 7 is designed for the largest of gardens. This lawn mower relies on boundary wire, but once installed, you don’t have to repeat the job, and this kind of set-up is good for large areas and more complicated layouts. It’s a shame that 4G can’t be activated later, but this feature along with the optional high traction wheels are limited to the more expensive Evo model.

Introduction

The largest model in the new line-up, the Stihl iMOW 7 has been designed to work in the largest gardens, able to cope with up to 5000m². It’s a reliable, powerful and configurable robot, but just be aware that it’s only with the Evo versions of the product that you get mobile connectivity.

Design and features

• Needs perimeter wire (available separately)
• Bluetooth and Wi-Fi connection
• Electronically adjustable height adjustment

The Stihl iMOW 7 has the biggest cutting capacity out of the company’s new robot mowers, supporting lawns of up to 5000m². For smaller lawns, there’s also the iMOW 6 (up to 3000m²) and the iMOW 5 (up to 1500m²). All three models are very similar, and operate in the same way, so the difference is in lawn size and price.

The regular iMOW version, which I have on review here, is finished in the standard orange and white colours of Stihl’s other products, such as the Stihl RMA 339  lawn mower. This version has Wi-Fi and Bluetooth connection options for controlling the robot.

With Wi-Fi connectivity, how good this is depends on how strong your network is and how far into the garden it reaches. It’s likely that, if you have a garden approaching the 5000m² maximum size, you’ll find that the robot drops out of Wi-Fi range during operation.

If you want constant contact with the robot lawn mower, you’ll need to upgrade to the Evo version of the product, which is available as the iMOW 5 EVO, iMOW 6 EVO and iMOW 7 EVO. These versions are distinguishable via their black and green finish and integrated 4G SIM.

It’s a pricey upgrade, with each EVO version costing £500 more than the regular version, although there are no more ongoing costs beyond this.

All versions of the new iMOW series need to be installed with boundary wire, which costs extra. You can handle the installation yourself, following the guidelines in the manual, which require the wire to be placed 37cm from a perimeter or obstacle, such as a pond. Stihl dealerships also offer professional installation, which could be a good option, particularly if you have a complicated layout.

Boundary wire starts at the docking station, which is screwed into the ground and must be located near a power socket. It’s a very similar docking station to those other robot lawn mowers use. The standard version leaves the robot exposed to the elements, but there’s an optional sun canopy that protects the iMOW 7 from heat, dirt and UV, which may be worth buying if you have the mower located in direct sunlight.

With this model, the boundary wire runs around your garden, and a third wire runs from the docking station to the boundary, which helps the iMOW 7 find its way home. This system is similar to that used on the Husqvarna Automower 405X.

Although there are robot lawn mowers that don’t need a guide wire, such as the Segway Navimow i105E, I think that they’re better suited to smaller and less complicated lawns; boundary wires make a lot of sense when the layout is more complicated and the mowing area larger.

Having a wire does mean it’s harder to change the layout of your garden, as the wire has to be moved, but the iMOW 7 does support zoning in the app, splitting the garden into areas. That’s useful for very large gardens, as it makes the mower more efficient. Again, it’s a good reason to pay for installation and have the mower set up correctly.

With its chunky wheels, the iMOW 7 can handle slopes of up to 40%, which is huge and should cover most gardens. If you have tougher terrain to deal with, you’ll need to buy the Evo version of the product, which has optional traction wheels that extend the gradient support to a massive 60%.

Underneath, the iMOW 7 has a cutting deck that takes three spinning blades. It’s a good choice as the blades are easier to maintain than the single bar blade the the older generation used. In fact, here, the blades can be removed without any tools, so it’s a quick changeover when required. With a cutting width of 28cm, the Stihl iMOW 7 can cover a lot of area relatively quickly.

This robot ditches the LCD screen of the older Stihl iMOw RMI 422 PC, as all of the programming and control options are via the iMow app. There are basic controls on the back, including a Stop button for emergencies (the robot will automatically stop if it’s lifted or flipped over), plus buttons to start or stop a cutting session.

For the most part, you’ll spend your configuration time in the app, which is generally easy to use. I like the motorised cutting height adjustment, which goes between 20mm and 60mm, which is enough variation to suit how you want your lawn to look.

Performance

• Dynamic mowing plan
• Excellent cutting
• Neat obstacle avoidance

The main aim of a robot lawn mower is to do all of the cutting for you. Via the iMow app, once the garden size has been input, a default schedule is created. That’s a handy starting point, although you can adjust the schedule to suit you, such as avoiding days when you know you’ll normally be outside. Stihl, quite rightly, suggests that you avoid mowing at night to protect any creatures that come out at night.

If you don’t want to follow the schedule, you can send the Stihl iMOW 7 out manually to perform a cut at any time.

This robot has ultrasonic sensors that allow it to detect larger objects and slow down as it approaches them to cut as close as possible. Testing in my garden, I found that the Stihl iMOW 7 moved gently around larger objects, but it can and will run over smaller objects, which required the robot to be put back in the dock and reset to go again.

I found that the robot moved well and didn’t get stuck moving across the grass, with its wheels powerful enough to push it through bumpy ground.

That’s a safety feature, and it’s important that the lawn is kept clear of small objects, such as cables, tools and balls, before it goes about its business.

A rain sensor on the robot is useful, as the mower can stop in its dock when conditions aren’t suitable for mowing.

Allowed to run for a couple of months, I found that the Stihl iMOW 7 cut my lawn brilliantly. On the odd run it would miss a patch of grass, but in the long-run, the mower catches everything, with the cuttings mulching down into the lawn and feeding it.

The result was a perfectly manicured lawn that was lush and springy to walk on. That’s the result that you’d hope for and expect.

It’s worth inspecting the Stihl iMOW 7 once a week and check that the blades are clean and don’t need replacing. In winter, it’s worth stowing the mower inside, and Stihl recommends an annual service by one of its dealers: for a product this expensive, that’s good advice.

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