I Spent Weeks Testing Robot Lawn Mowers. Here Are 6 Things That Surprised Me

CNET

4 days ago

I spent the end of my spring and the beginning of my summer turning my backyard into a parking lot to test the best robot lawn mowers. In the process of doing that, I learned a lot about their benefits and their shortfalls. One of the biggest lessons was that, like most forms of automation, they can be a real pain to set up initially, but once they're ready to go, they save you a ton of effort and time compared with regular electric lawn mowers.
I didn't expect that initial annoyance going into that project, but I think it's important to document those pains so you can avoid them in the future. Here are some of the lessons I learned about the obstacles you'll have to overcome if you decide to pull the trigger on a robot lawnmower.
Way more wires than I expected
The wires running through my yard for the robot lawn mower. It's not the most attractive sight.
Adam Doud
The 800-pound gorilla in the room for robot mowers comes in the instructions that every mower company sends along with the robot. First, there are a ton of wires. You might need to run power to the base station or to the RTK beacon or both. If you're unfamiliar, RTK stands for Real-Time Kinematic, a beacon that corrects a mower's coordinates to improve accuracy.
The mower companies tell you not to place the mower within 7 feet of a building or under a tree. They also tell you not to run wires through the grass. But if you're not supposed to place the base station under a tree or within 7 feet of a wall, where exactly are these wires supposed to go?
I also ran into an issue where an animal chewed through a wire to an RTK station, and I had to drive 70 minutes (one way) to a service center to get it repaired. You'll want to protect your wires where you can. Burying them is one way of doing this. Since I had to run them around a garden, I ran them through pool noodles. It's crude, but effective.
I had to use a pool noodle to hide the wires. It's not attractive, but it works.
Adam Doud
Not all yards will work well
My backyard is almost entirely covered by a large tree, so it was difficult to find an appropriate installation space. Ultimately, despite instructions to the contrary, I had to line the mowers up next to my house. Only the Yarbo Lawn Mower and Airseekers Tron couldn't handle that; the rest were all fine.
My yard isn't the simplest one for a robot lawn mower to navigate, with a large tree, trampoline and other obstacles.
Adam Doud
Yard boundaries are another thing to consider. Do you have a fence? Will the gate need to be opened to let the mower through? Do you have an insane neighbor who will set your yard on fire if a robot dares tread upon his property? Is there a boundary between your and your neighbor's property, like a fence, sidewalk or driveway? These are all important things to consider before taking a four-figure plunge into the world of robot mowers.
I hope you have power outlets outdoors
If you don't have an outdoor power outlet, you'll need to install one to set up your robot lawn mowers. I had to jerry-rig this one out of my outdoor light.
Adam Doud
One other important factor to consider: Do you have outdoor power? These mowers all need to be plugged in. In my case, I converted an outdoor lighting fixture into an outdoor plug; that may or may not be an option for you. The cords that mower companies provide you may not be long enough to get from the power to where the base station or RTK beacon needs to be, so you might have to buy extra cables, or you may need an electrician to come out and install a new outdoor outlet.
Staying in bounds can be hit or miss
The Eufy E15 was one of the easiest robot mowers to get working out of the box. I really liked its simpliciy.
Adam Doud/CNET
All the mowers I tested handle boundaries using GPS and an RTK beacon. The only exception to that is the Eufy E15 mower, which uses GPS and vision systems to navigate. Boundaries are typically set by manually controlling the mower around the property and saving a map. Obstacles are a different issue, though.
Various mowers handle obstacles differently. Most robot mowers handle obstacles using vision sensors, and those that don't are not my favorites. The Sunseeker X3 has a bump sensor, like what you'd find on a robot vacuum, but I found it to be too sensitive and it would prevent good mower coverage. Others use a radar module, which I also came away less than impressed with -- or at least my toes did, since it wouldn't always stop before hitting my foot.
The Sunseeker X3 was one of the best robot lawn mowers I tested.
Adam Doud
All the mowers allow you to set no-go zones for areas where additional sensors don't quite do the job. If a mower consistently gets stuck or otherwise has problems, you can set a no-go zone and the mower will ignore that particular patch.
The common theme is that the more sensors you have working for you, the better off you'll be, but my favorites in order are: GPS, vision sensors, radar sensors and bump sensors.
Maintenance wasn't demanding, aside from blades
The mowers will need their blades replaced periodically as they wear down, but that's not too difficult to do.
Adam Doud
Robot lawn mowers are generally easy to maintain because they're designed to be outside. The most maintenance you'll have to worry about is blades and winterizing. Blades are fairly easy -- every mower I tested included a set of replacement blades. Keep in mind, these are small razor blades, so they may start to get dull a lot more quickly than a traditional push mower. They also might be more prone to breakage, so be sure you pick up any sticks or other debris in your yard, especially after a bad storm.
Speaking of blades, these tiny razors that ship with the mowers make the mower more efficient by drastically reducing the weight the motor has to spin, but it comes with the trade-off that the blades may not last long. Upon concluding my first round of testing, I noted that most of the blades were starting to show signs of rust, which is not encouraging after only two months of use. That said, summer in Chicago is only about four to five months long, so one set of blades might make it, but if you live in an area where you're cutting the grass year-round, your blade budget will need to be higher.
One of the blades of the robot lawn mower started picking up rust already after just a month or two of use.
Adam Doud
Beyond that, the main thing you have to do is bring the mower in for the winter. Preferably, before the first frost, you'll want to pack up the mower's components and bring them out of the elements. Each mower has its own set of steps and recommendations, but in general, you will want to store the mower in an environment that won't get frost. Your garage or shed may work.
If possible, you may also want to remove the battery and store it inside your home at room temperature. You can also take this opportunity to clean the mower and the base station and even change blades.
Your work is not done, most robot mowers will miss spots
Just remember that a mower won't do all the work for you. If you have any narrow paths of grass in your lawn, the robot won't handle those well. You'll also still need to go out and trim the grass around the edges. You might also find some area the mower decided to skip for some reason -- maybe a sensor was tripped and the mower skipped an area. You'll still need to stay on top of things to make sure your lawn stays the best it can be.
Our best overall, the Segway Navimow X390, is the most expensive robot mower you can get, but it offers the best performance too.
Adam Doud/CNET
Are robot lawn mowers worth it?
Overall, the main thing I learned from my experience is that robot lawn mowers are ultimately worth it despite their foibles, an opinion I share with other CNET reviewers who've taken them for a spin. They eliminate a task that many homeowners don't like in the first place. Plus, they're easy to adjust. When the summer started getting too hot, I adjusted the cutting height higher to help the grass thrive. One day, when we were hosting a party, I just shifted the automatic mow time to a different day.
Once you power through those initial steps, the mower takes care of itself. Just make sure other people in the family have access to the mower, so if you're in London, and the mower gets stuck, they can go help it out — and yes, that's based on a true story. But other than that, kick back and enjoy your perpetually shorn grass and your neighbor's envious glances.