Beyond the Health and Appearance of Your Lawn

McCulloch ROB S400 Review

McCulloch ROB S400 Robotic Lawnmower Review (2021)


McCulloch ROB S400 is built for lawns up to 400 m² (or 0.1 ac.) in size where the slopes aren’t steeper than 19.3° (or 35 percent). It’s otherwise an autonomous robotic lawnmower using a 18 V 2.0 Ah lithium-ion rechargeable battery running on electric power. It mulches grass and goes at it in a random pattern using 3 pivoting razor-like blades attached to a rotating disc that make up the cutting system. The robot mower operates quietly (up to 57 dB) and maintains your lawn at a cutting height of 20-50 mm (or 0.8″ to 1.97″).

Check its price here: McCulloch ROB S400 Robot Mower.

McCulloch ROB S400 Package

Apart from that, it’s a fairly simple of a robot lawn mower, though you do get plenty of extra functions to cut closer to the edge, cover inaccessible zones, save energy, and so forth. It more or less does everything to some extent and includes all the essential mowing, safety, and security features by default. What is lacks is a rain sensor and proper ability to remote control from afar (connection via Bluetooth instead of internet).

Robot mowers are an actual life hack in my opinion as they save me a lot of time. Although the initial cost can be daunting, considering that the running costs in general are super low on top of the time saved, I would never want to go back to doing it manually.

Quick Overview for the Hasty

McCulloch ROB S400 robot mower measures 55 cm x 38 cm x 23 cm / 21.65″ x 14.96″ x 9.06″ (length x width x height) and weighs 7.3 kg (or 16.09 lbs).

McCulloch ROB S400 Robot Mower

Here’s a useful overview of robot mowers in general: “Robot Lawnmower Buying Guide”.

At base value, McCulloch ROB S400 features tilt, lift, and collision sensors, but no rain sensor. Apart from the extra functions that let the robot mower cut closer to the edge, cover inaccessible zones, save energy, and so forth, it’s much like your typical robot mower. Remote control is limited to Bluetooth connection though.


  • simple, practical, and effective
  • more for less – affordable


  • remote control with Bluetooth rather than Wi-Fi
  • doesn’t do your dishes


For extra cost you could get a wall hangar or a mini garage, but these are something you could build yourself or simply just skip entirely.


Who’s Behind McCulloch ROB S400 Robotic Lawnmower?

McCulloch UK Ltd is a brand within the Husqvarna Group.

This Swedish company, currently the global leader in robotic lawn mowers by the way, acquired the rights to the American based McCulloch brand first in Europe and then on the North American markets in 1999 and 2009 respectively.

Also, Gardena, another brand dealing with robotic lawn mowers, is also part of Husqvarna Group. Just saying.


What Are the Specifications of McCulloch ROB S400?

  • Dimensions – 55 cm x 38 cm x 23 cm / 21.65″ x 14.96″ x 9.06″ (length x width x height)
  • Weight – 7.3 kg (16.09 lbs)
  • No load speed – 2500/min (rounds per minute)

McCulloch ROB S400 Specifications

  • Max cutting area – 400 m² (0.1 ac.)
  • Maximum slope for cutting area – 19.3° (35 percent)
  • Max incline for perimeter wire – 5.7° (10 percent)
  • Battery pack – 18 V 2.0 Ah lithium-ion rechargeable battery
  • Mowing time – 65 min (avg.)
  • Charging time – 60 min (avg.)
  • Cutting width – 16 cm (6.3″)
  • Cutting height – 20-50 mm (0.8″ to 1.97″)
  • Cut height positions – 4
  • Volume level – up to 57 dB


What Are the Features of McCulloch ROB S400 Robot Mower?

McCulloch ROB S400 robot lawn mower has many features.

1) General:

  • autonomous charging and mowing
  • silent operation (up to 57 dB)
  • Bluetooth connectivity
  • low running costs

2) Control System:

  • manual control panel keypad
  • remote control with app
  • alert messages

3) Navigation system:

  • random mowing pattern
  • relies on a perimeter wire
  • Lawn Coverage function
  • Scheduling options (4)
  • Lawn Shield function
  • built-in standby period
  • Avoid House Collisions function
  • Drive Past Wire function
  • park mode commands (2)
  • operation mode commands (3)
  • collision sensor

4) Charging system:

  • ECO mode

5) Cutting system:

  • mulching system
  • cutting height adjustment dial
  • 3 pivoting small blades

6) Safety features:

  • emergency STOP button
  • collision sensor
  • tilt sensor
  • lift sensor

7) Security features:

  • Time Lock function
  • pin code
  • alarm


1) General Features

Automatic charging and mowing cycle 
Much like any robot mower out there, the McCulloch ROB S400 is also autonomous. That means it will mow and recharge on its own as per the schedule.

Silent operation (up to 57 dB) 
Most robot mowers are somewhat quiet, sound level being around 60 dB. The one under review can reach up to around 57 dB, which is fairly quiet on the market of robot lawn mowers. This can be compared to normal conversations sounds levels. Now compare that to your regular motorized push mower that roars at around 90 dB and even up to 110 dB. You can read more here: “How Loud Are Robot Mowers?

Bluetooth connectivity
I’ve gotten the impression that this robot mower can be paired with a smartphone or a tablet via Bluetooth connection using an app. This would effectively allow you to control things remotely.

Low running costs 
Apart from the initial purchase, there are also the running costs involved. Electricity and certain replacement parts factor into it. The battery will last anywhere from 2 to 6 years while the blades need changing roughly twice per mowing season (3 at a time). When it comes to electricity, a 18 volt 2.0 Ah battery uses roughly 0.036 kWh (calculated here). It would cost a couple of cents to keep it running for the whole day. It wouldn’t be much more than a few tens of bucks per mowing season like that.


2) Control System

Control panel keypad 
McCulloch ROB S400 has quite a few buttons on control panel with a screen at the top for feedback, and it’s all under a protective cover for extra protection against the atmospheric elements. You’ve got arrow keys and a few more intuitive buttons to play with. Overall, you can configure scheduling options, mess with mowing modes, security settings, and more.

McCulloch ROB S400 Control Panel

Remote control 
This robot mower features over-air connectivity via Bluetooth which allows you to pair the mower with a smartphone or a tablet using an app. With it you can control its settings and give the robot mower some mowing commands and the like remotely.

The screen gives feedback in a simple manner when so as to confirm your actions while configuring settings or when there’s something wrong with the system and whatnot. The app gives a better overview of things as the manual control panel screen is a little more limited in that regard.


3) Navigation System

Mowing pattern: random
There are only a couple of robot mowers on the market that don’t mow in a random pattern, but that doesn’t mean there’s anything wrong with it – it’s a reliable practical low-effort solution.

Relies on a perimeter wire
Again, there’s only a few robot mowers that can do without a perimeter wire. It might seem bothersome to install, but honestly it poses less hassle in its simplicity – also a practical low-effort solution. The wire itself is electrified (not harmful) making a loop around the cutting area and thus defining the mowing area for the robot mower. It connects again at the recharging station. It partly helps the mower find its way back to the recharging station, too. The wire can be installed tightly against the ground or a few centimeters underneath.

Lawn Coverage function
This function allows the McCulloch ROB S400 robot mower to reach certain mowing areas where it otherwise might hardly ever reach. By following a guide wire out of the recharging station that eventually meets with a perimeter wire at some point somewhere is where it starts mowing from. It’s called area 1 (or zone 1). You can also set a % of times it should start from that aforementioned point (area 1) instead of just starting from the charging station 100% of the time. (this guide wire also helps the mower get back to the charging station.)

McCulloch ROB S400 Guide Wire Meets the Perimeter Wire

Scheduling options
4 options to schedule mowing times: Wizard, Day mode, Night mode, and Advanced (a.k.a manual mowing schedule configuration). The “Wizard” option suggests a schedule based on the lawn size you have to provide, and if your lawn is smaller than the max capacity, it may also ask you to pick the days it won’t be mowing at all. The Day mode means that the mower starts mowing from 08:00 and goes on according to the schedule. Night mode starts at 20:00. And the Advanced options allow you to select the mowing times yourself.

Lawn Shield function
This is an additional function you can enable that seems to override the aforementioned scheduling options to some extent by adjusting the schedule depending on lawn growth. When there’s something to akin to a drought, it will more or less know about it from the length of the grass and simply won’t mow in order to protect your lawn from needless stress. And when it’s raining more often than usual making the grass grow quicker, the mower will schedule itself to run more often to keep up with the growth. You can give this function more clearance by selecting a higher frequency level (from the 3 levels) in the settings.

Built-in standby period
This one is simple, but it’s hard to convey its purpose. So the standby period is when the mower just sits at the charging station doing nothing. Since this robot mower max capacity is 400 m² (0.1 ac.), the standby period has to be 14 hours a day at the minimum. That means 10 hours of operating hours per day (within 24h) at the maximum (can be less). So if you’ve set things on the Day schedule (08:00 to 22:00), the operating hours max would be from 08:00 to 18:00 (10 hours), and standby would go into effect from 18:00 to 08:00 (14 hours). More info in the manual.

Avoid House Collisions function
And this function is for when you’re concerned about the McCulloch ROB S400 bumping into the robot mower garage (if you have one) wherein it might, one bump at a time, damage both the garage and the mower itself over time. With this enabled, it is less likely to bump into the garage by simply not mowing around the charging station. With this enabled you have to account for uncut grass around the charging station which you ought to trim manually I suppose.

Drive Past Wire function
It’s a default feature with the factory setting being on 32 cm (12.6″). This is essentially a cut to edge feature where the robot mower goes over the perimeter wire to cut closer to the edge. You can adjust the length at which it goes over the wire from 20-40 cm (7.87″-15.75″).

Park mode commands (2)
Upon pressing the home button, it opens up 2 ways things go down: either “GO Home, ROB, you’re drunk, and stay there!” or “Go home & wait.” Essentially, instead of having to manually carry it back to the charging station, these 2 allow you to do that with a press of a button. The 1st (“Go home & stay”) commands the mower to return to the charging station and to stay there until you give it a new command manually. The 2nd option makes it go back, but allows it to continue working starting from the next scheduled mowing time or so.

Operation mode commands (3)
Secondary area, Power Cut, and Spot Cut. The secondary area mode is essentially a manual cutting mode for an area where the mower wouldn’t reach by itself. You ought to extend the perimeter wire of the main area to that secondary area, so as to define that area still, simply carry the mower to that area and launch it with this mode enabled. It will mow until it runs out of battery. Power Cut simply just forces the mower to go and start mowing even outside the scheduled mowing times, but only for up to 3 hours. It is not possible to override a standby mode however. Spot Cut is meant for cutting a specific smaller area – you carry the mower to the spot, launch it with this mode, and it will start mowing it in a spiral pattern. That’s actually pretty cool.

Collision sensor 
A simple but practical bump sensor and not the more sophisticated ultrasonic sensor that can detect the obstacle from afar. With this bump sensor, the robot mower will first bump into obstacles to register them as such and alter the mowing direction based on the information acquired that way.


4) Charging System

As with all robot lawn mower today, McCulloch ROB S400 charging and mowing cycle is automatic, too. That means it will mow and recharge all on its own as per the schedule.

McCulloch ROB S400 Charging Station


ECO mode
The ECO mode for McCulloch ROB S400 is not an ideal energy saving feature requiring babysitting as it’s only a temporary thing, but it’s something. When the mower is not mowing and is charging or doing nothing, you can activate this ECO mode upon which a green led light starts flashing on the charging station. Electricity to the wire and so forth is shut. It won’t start mowing or doing anything until you press the STOP button and deactivate this ECO mode. Not so much of an active energy saving feature unfortunately, but the running costs even without it are super low.


5) Cutting System

Mulching system 
Mulching is where the grass is cut, but not collected, rather dropped back down onto the soil as a fertilizer. It works because robot mowers are designed to cut more often and nibble the grass tips rather than cut off a huge chunk once a week as it is for regular mowers. Mulching keeps the grass fairly healthy. If you wanted a truly healthy looking lawn, all that’s left for you to do is aeration.

McCulloch ROB S400 Cutting System

Cutting height adjustment feature 
The cutting height can be adjusted between 4 options: 20, 30, 40 or 50 mm (0.8″ to 1.97″).

3 pivoting small blades 
McCulloch ROB S400 robotic lawnmower has 3 pivoting razor-like blades that are attached to a rotating disc that make up the cutting system. There’s also the solid type of cutting system, but this pivoting blade type of a cutting system here is quietersafer, and more energy efficient in comparison. As for the negatives, the pivoting small blades attached to a rotating disc are a little less efficient at cutting things. There’s also the higher risk of the small blades just breaking off, but the chance of it actually happening is fairly low.


6) Safety Features

Emergency STOP button 
Apart from McCulloch ROB S400 robot lawn mower having a big emergency STOP button, being fairly quiet (up to 57 dB)moving slowly, and having a considerably weaker motor when compared to your regular lawn mower, meaning it will have a hard time with anything other than grass, along with blades being small and tucked deep under the chassis, there are a few more tricks under its belly (learn more: “Robotic Lawnmower Safety”).

McCulloch ROB S400 Emergency STOP Button

Collision, tilt, and lift sensors 
Collision sensor the McCulloch ROB S400 has is essentially just a bump sensor and NOT the ultrasonic sensor that detects and avoid collision with obstacles entirely helping it navigate. The bumps sensor also acts a safety measure because instead of pushing on forever, it will change direction upon somewhat light bump into things. Tilt and lift sensors will stop the blades almost instantly when the mower is tilted or lifted.


7) Security Features

Security levels
There are 3 security levels: low, medium, and high. The picture is self-explanatory, but I’ll still go over it in words. At the “Low” only Time Lock function is active. At “Medium” it’s PIN-code and Time Lock function that are active. And, you might have guessed it, at “High” security level there’s also the alarm function on top of the PIN-code and Time Lock function. A little more info on those 3 functions down below.

McCulloch ROB S400 Security Levels

Time Lock function
When the PIN-code is not entered for 30 days, the mower gets locked and a PIN code has to be entered in order to unlock it. So that means you can’t get away from having to remember or write down the PIN code. This function is present even at the lowest security level and the aim is to prevent unauthorized access in the long run.

Pin code 
At the medium or high security level the PIN code prompt comes up more often. E.g when you press the STOP button while it’s working or when you start up the mower, you ought to inset the correct PIN code to proceed. At first there likely is no PIN code, so you have to create one from scratch (you can change it later on). Try not to forget the PIN code once you’ve created it! (it is not possible to use 0000 as the PIN code)

At the highest security level, that is at “High”, the alarm becomes active. It goes off when the mower is lifted while it’s working or when the correct PIN code is not entered within 10 seconds after pressing the STOP button. You can stop the alarm by entering the correct PIN code once it has gone off for one reason or another.


Additionally, you could:

Hide from bypassers
Try installing the charging station somewhere hidden from bypassers for added protection.

Use a sticker
You can custom make a sticker with fake information about its security features and put it on the mower for the potential thief to kindly return the mower once they notice it – once they realize that they can’t do anything with it without knowing the PIN code, instead of just leaving it somewhere, they might return it knowing they could still get off easy. They might…

Fake surveillance system
Putting a camera, even if fake, in an obvious easy to spot location overlooking the area will at least make the potential thief think twice.


What’s Included In the McCulloch ROB S400 Package?

Robotic Mower
Charging Station
Installation Manual
150 m Boundary Wire
Additional Guide Wire
Extra Cutting Blades (3)

Boundary Wire Staples (200)

Nails, screws, hex key, power supply & cable, wire connectors, and the like.

Additionally, for extra cost:
Mower house


Should You Buy the McCulloch ROB S400 Robot Lawn Mower?

A fair reminder that this robot mower is not the only one out there. McCulloch ROB S400 is competitively priced and packs great value for a lawn of 400 m² (0.1 ac.).

It might seem like too simple of a robot mower, but that’s the beauty of it – it’s practical and reliable while offering much more options than your typical robot mower. And on top of all that, it’s of good quality, being part of the Husqvarna Group, the market leader when it comes to robot lawn mowers. So if you were looking for good quality at a competitive price (affordable), and the features were right for you, this is quite the option.

It might not be for you if your garden layout was very complex and/or the slopes were large and steeper than 10% (or 5.7°) and you wanted cut height to be less than 20 mm (0.8″) or more than 50 mm (1.97″). Or when you wanted remote control to be via Wi-Fi rather than Bluetooth which kind of requires to be close by with your smart device.

You can check its price here: McCulloch ROB S400 Robot Mower.

Should You Buy the McCulloch ROB S400 Robot Lawn Mower?


How To Install McCulloch ROB S400?

When it comes to the setup, you’re looking at the installation of the perimeter wire and the charging station. The whole process can take a few hours (check with installation manual). It is all very well documented.

For perimeter wire, there are a few requirements on how far it should be from the edge and so forth. You can get good info on everything from the installation guide. But for the sake of the review, make sure your lawn doesn’t have steeper than 10% (5.7°) slopes where you’d place the perimeter wire. The robot mower itself can handle steeper slopes. Additionally, you can either bury the wire or lay it tightly against the grass instead using the staples. Ultimately it is better to bury it though.

Another thing is the charging station. Setting this up is fairly straight forward (check with installation guide), but I’d like to point out a few key things still. They’re mainly to do with the charging station placement requirements:

  • It must be close to a wall socket;
  • preferably under shade & cover;
  • install on a relatively flat surface outdoors;
  • install it somewhere out of sight from bypassers;
  • leave at least 2 m (6.6 ft) of free space in front of the charging station;
  • if you installed the charging station to an island, make sure the guide wire runs into the island also.

McCulloch ROB S400 Guide Wire Island


How To Take Care of the McCulloch ROB S400 Robot Mower?

As is with all robot lawn mowers, McCulloch ROB S400 robotic lawnmower, too, requires very low maintenance:

  • clean regularly;
  • replace cutting blades when need be;
  • replace rechargeable battery when it seems almost dead;
  • install charging station in shaded area to protect the mower from the elements;
  • don’t forget to unplug the power supply connected to the charging station you left outside for winter;
  • when storing the robot mower itself, charge fully, turn off, clean, and place in dry indoor conditions, and avoid leaving in freezing temperature.



McCulloch ROB S400 is built for lawns up to 400 m² (or 0.1 ac.) in size where the slopes aren’t steeper than 19.3° (or 35 percent). It’s otherwise an autonomous robotic lawnmower using a 18 V 2.0 Ah lithium-ion rechargeable battery using electric power. It mulches grass and goes at it in a random pattern using 3 pivoting razor-like blades attached to a rotating disc that make up the cutting system. The robot mower operates quietly (up to 57 dB) and maintains your lawn at a cutting height of 20-50 mm (or 0.8″ to 1.97″).

Apart from that, it’s a fairly simple of a robot lawn mower, though you do get plenty of extra functions to cut closer to the edge, cover inaccessible zonessave energy, and so forth. It more or less does everything to some extent and includes all the essential mowing, safety, and security features by default. What is lacks is a rain sensor and proper ability to remote control from afar (connection via Bluetooth instead of internet).

McCulloch brand
McCulloch UK Ltd is a brand within the Husqvarna Group. And the latter is the global leader in robotic lawn mowers. McCulloch robot mowers are competitively priced and, similarly, of good quality.

What’s in the package
McCulloch ROB S400 package includes the robot lawn mower itself, a charging station, 150 meters (approx. 492′) of perimeter wire, 200 boundary wire pegs, and some manuals, but also the power supply & cable, screws, nails, wire connectors, and the like.

Where to buy
It’s simple, buy here: McCulloch ROB S400 Robot Mower.



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One comment

  1. Hlo

    I’ve had this for a few months now and it works well. It’s mowing even under the trampoline without problems. I can use cheap blades that fits other Husqvarna models. It cannot cut very close to the the wall but I think this is normal for most brands.

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