Robomow RC304u robot lawn mower review

Robomow RC304u Robot Lawn Mower Review

The Robomow RC304u is a mid-range robot lawn mower from Friendly Robotics. The Robomow RC304u is a great little machine and is my top pick of all the robot lawn mowers that can manage lawns of between 600 m² and 1000 m².

It stands out from the competition due to a number of features including its superior edge cutting ability, turbomow feature, and excellent integration of smart features. It has a modern design, which looks sleek and stylish, and the dark green colour will look great in any garden. You can check the current price of the Robomow RC304u at the following link. 

Friendly robotics have been making robot lawn mowers since 1997, with the introduction of the Robomow Classic. Since then, there has been a gradual evolution of their machines and brand.

Today, they stand as one of the leaders in the robot lawn mower market. Their robot lawn mowers have a number of differentiating features, which give them some unique benefits and a few drawbacks compared to their competitors.

Design And Main Features

The Robomow RC304u can cut lawns of up to 1000 m² in size. This assumes that your lawn is fairly flat, has a simple rectangular shape, no obstacles or additional zones and that your lawn grows at a modest pace. If you have a very complicated lawn with a lot of obstacles, it may only manage to cut a smaller area. In fact, Robomow advise that the ideal lawn size for the Robomow RC304u is only 500 m².

Therefore, the decision of whether to go for this model will rely on you assessing your lawn and making a decision about how complicated it is. If you have a complicated lawn, you may be better to step up to the Robomow RC308, which is the Robomow’s next model up in the range.

The Robomow RC304u has a cutting width of 28 centimetres and will cut your lawn to a height of between 15 and 60 mm depending on your preference. It can manage slopes up to a gradient of 36%, which is a 20 degree slope angle.

The Robomow RC304u has an edge cutting feature which is superior to some of the other competing brands on the market, and will result in less time being spent trimming and maintaining the edges of your lawn. It has a modular design, which makes replacing spare parts easy.

It also has a turbo mode which allows extra power to be supplied to the cutting blades whenever needed, such as when cutting through long grass. This is particularly useful for your first cut with the Robomow RC304u and for the first cut after winter storage.

It also has a smartmow feature to improve the navigation of the robot lawn mower around your garden and increase the efficiency with which it gets your lawn cut.

Robot lawn mowers from Robomow are generally more noisy during operation than competing brands. This is due to the cutting technology that is used in Robomow robot lawn mowers. There are advantages and disadvantages of this, but it is worth bearing in mind that this is not the most silent robot lawn mower on the market.

Pros And Cons


  • Sleek design
  • Excellent lawn edge cutting ability
  • Turbomow mode makes light work of longer grass
  • Excellent dealer network for spares, repairs and installation if required


  • Louder than comparable robot lawn mowers
  • Greater power consumption than comparable robot lawn mowers
  • Some uncertainty about lawn size it will handle

Comparison To Similar Models

The following tables outlines the main alternatives to consider if you are looking for a robot lawn mower and your lawn is approximately 600 m² to 1000 m².

MowerRobomow RC 304uHusqvarna 310McCulloch
ROB R1000
Max Cutting Area1000 m²1000 m²1000 m²
Maximum Slope20°22°14°
Cutting Time45-50 minutes70 minutes65 minutes
Charging Time50-70 minutes60 minutes50 minutes
Noise Level64-69dB60dB59dB
Weight11.1 kg8.5 kg7 kg
Dimensions63x46x21 cm63x51x25 cm59x44x26 cm
Current PriceCheck PriceCheck PriceCheck Price


Installation of the Robomow RC304u is very straightforward and I was impressed by the instructional materials which were supplied in the box. Robomow also has an excellent Youtube channel with helpful videos which can guide you through the installation process.

Contents Of The Box

The Robomow RC304u is very well packaged and was protected from the risk of damage during delivery. On opening the box, I found the following.

  • Robomow RC304u
  • The Base Station
  • Perimeter wire
  • Power supply
  • Blade removal tool
  • Pegs
  • User guide
  • Roboruler for measuring the distance from the edge of the lawn to install the perimeter wire
  • Base station stakes
  • Plot connectors
  • Wire connectors
  • Cutting height extender

To install the Robomow RC304u, you will need a hammer, a pair of pliers and a small flat screwdriver. The first thing you should do is assess the shape of your lawn. Robomow splits this down into four different types.

  1. Lawns with only one main area.
  2. Lawns with a main zone and a secondary area that is connected by a narrow section.
  3. Lawns with a main zone and an unconnected second zone.
  4. Lawns with a mian zone, a sub-zone and a separate zone.

Thankfully, the Robomow RC304u will be able to manage all of these types of garden and the manual explains very clearly the installation process for each option.

Installing The Charging Station

The next step is to choose a good location for the charging station. There are four main things to keep in mind to help you pick a good location.

  1. Pick a location no further than 15 metres from a power outlet.
  1. There should be a minimum of 1.5 metres clear directly in front of the charging station, to allow smooth docking of the robot lawn mower.
  1. Minimum of 1 metre from a sprinkler head.
  1. Even and flat ground.

Installation Of The Perimeter Wire

robomow rc304u perimeter wire installation

Once you have chosen a location for the charging station for the Robomow RC304u, you should move onto installing the perimeter wire, before securing the charging station to the ground. You will need to use the ruler that comes supplied with the Robomow RC304u, which has the distances that the perimeter wire should be installed from the edge of the grass marked on it.

For lawn edges that are next to a flat path or drop, you should use the shorter distance on the ruler to position the perimeter wire. For walls or fences, you should use the longer distance on the ruler.

You should start by leaving 30 cm of perimeter wire where you will plug it into the back of the charging station and peg the first part of the wire down. Proceed to unwind the wire anti-clockwise around the edge of your lawn and put a peg in every few metres, measuring the distance correctly each time to ensure that the perimeter wire is at the correct distance from the edge of the lawn.

You should pull the wire so that it is flat to the ground. Take extra care at corners by putting the pegs closer together to ensure that the corners are smooth, rather than having any sharp angles.

Hard obstacles such as trees in the centre of your lawn do not need to be protected by marking them out with perimeter wire. Soft obstacles, such as flower beds or ponds will need to be marked out with perimeter wire, as the Robomow RC304u will not be able to detect the edges of these.

Dealing With Obstacles In Your Grass

Robomow RC304u perimeter wire around obstacles

For a soft obstacle such as a flower bed in the middle of your lawn, you should run the perimeter wire around the edge of your lawn until you get to the closest point to the flower bed. At this point you should run the perimeter wire directly towards flower bed until you get close to the edge.

Once close to the edge, you can peg the wire into the grass at the recommended distance specified by the roboruler. Having gone around the perimeter of your grass anti-clockwise with the perimeter wire, you should go round the obstacle clockwise with perimeter wire until you get back to the point you started.

You should put the pegs fairly close together to ensure that the curves are fairly smooth around the obstacle. Once you get back to the start, you should run the perimeter wire back to the edge of the grass. The section of perimeter wire going to the obstacle must be laid close to the section returning from the obstacle, but they must not cross.  

The Robomow RC304u will be able to detect the perimeter wire around the soft obstacle, and will cut around this obstacle with ease. The signal from the two bits of perimeter wire running to and from the obstacle will cancel each other out due to their proximity. The Robomow RC304u will ignore this and will pass over the top of this section.

Once you get the perimeter wire back to the edge of the lawn, continue around the edge of your lawn in an anticlockwise direction until you complete an entire circuit of your lawn with the perimeter wire.

You should put the last peg very close to the peg securing the first bit of the perimeter wire, so that both ends of the perimeter wire are sitting next to each other. You should trim the ends of the perimeter wire so that they are the same length. This will make it easy to plug them into the back of the charging station.

You should twist the two ends of the perimeter wire together to make it easier to attach the connector. You will need to strip the ends of the perimeter wire and insert both ends of the wire into a connector. The wire can be secured into the connector using a flat head screwdriver.

Once this is done, you should walk around the perimeter wire and add extra pegs anywhere where the perimeter wired is not flush with the ground. You should also ensure that all the corners are fairly smooth, and where extra pegs are required, you should make use of them.

Connecting the Charging Station

The next step is to place the charging station of the Robomow RC304u in its planned location. Align the charging station with the perimeter wire so that it is straight and the Robomow RC304u will be able to dock with the charging station without issue. You should use two of the charging station stakes to secure the back of the charging station in place, next to the end of the perimeter wire.

You can then proceed to connect the green connector holding the perimeter wire into the back of the Robomow RC304u charging station. Then connect the power cable to the charging station and peg it down to the ground towards the power socket. Connect the power supply to your power socket and a green light should appear on the charging station.

First Start Up

You’re now ready to give the Robomow RC304u a test drive. You should adjust the mowing height before you start. This can be done by turning the robot lawn mower over and using the cutting height extender tool. You can then go ahead and switch the Robomow RC304u on.

You will then be guided through a short setup procedure on the control panel to set the measurement units, date and time You can then test the base station position by placing the robot lawn mower 2 or 3 metres from the charging station and pressing ok.

The Robomow RC304u should then dock and undock with the charging station, confirming that your charging station is in the correct place. You can then make use of the final 2 charging station stakes to securely fasten the charging station to the ground. The next step is to test the perimeter wire. Simply follow the instructions on the control panel and press OK. The Robomow RC304u will undock from the charging station and follow the perimeter wire all the way around the perimeter of your lawn. If any adjustments are needed to the perimeter wire, you can complete these and then retest the position. If the Robomow RC304u is running without any problems, then you can set the robot lawn mower to work.


Robomow RC304u robot lawn mower in operation

Since installing the Robomow RC304u, it has worked flawlessly. After the initial setup, it calculates how often it needs to cut your lawn based on the size and complexity of your lawn. It also has a rain sensor and won’t start a scheduled cut unless it detects dry weather.  

The Robomow RC304u will work perfectly well in wet conditions, but it can cause some of the clippings to gather on the grass and the robot lawn mower can lose a little traction at times. The rain sensor, as well as the frequency and duration of lawn cutting can be adjusted in the settings menu or via the smartphone/tablet app.

Generally, robot lawn mowers are designed to cut your grass more frequently than a conventional lawn mower. There are two reasons for this.

Firstly, One of the significant attractions of robot lawn mowers is that they can give you a lawn that looks freshly cut everyday. Secondly, robot lawn mowers mulch your clippings and return them to the grass. Frequent mowing allows the cuttings to fall into the lawn rather than being visible on top of it.

One important point to note with the Robomow RC304u is that you need to make sure that your lawn is free of small objects. small children’s toys, sticks or pine cones, for example will not be detected by the collision sensors. objects such as these can cause excessive wear and tear on the blades of the Robomow RC304u.

Although the Robomow RC304u robot lawn mower has smartmow features to improve efficiency in the way it cuts your lawn, it is not a particularly intelligent robot. Generally, it will move in a straight line until it gets too the perimeter wire, before turning and moving in a different Direction. Having said this, I have been more than impressed with how it keeps my entire lawn freshly cut and looking fantastic all the time.

Mowing Features

Robomow RC304u cutting blades

The Robomow RC304u has a number of useful cutting features. Firstly, it has tougher blades and a stronger motor than a number of competing brands. This enables it to cut through longer, more dense patches of grass, and can reduce the risk of any patches not being cut well.

The smartmow feature of the Robomow RC304u enables it to have a more efficient mowing pattern than competing robot lawn mowers. It is able to do smooth turns when it reaches the edge of your lawn and continue in another direction. This is in contrast to a number of other robot lawn mower brands. Many competing models continue until they get to the perimeter wire, before stopping, backing up, turning and moving in a different direction.

The turbomow feature of the Robomow RC304u allows faster and stronger mowing of grass when it is needed. An example of this would be the first cut of the growing season after the robot lawn mower has been brought out of winter storage. During turbomow mode, the Robomow RC304u reduces it’s moving speed, increases the RPM of the blades and increases the cutting hours This leads to your lawn very quickly looking neat and tidy again.

The Robomow RC304 has a great edge cutting feature. This is a setting that can be activated to make your robot lawn mower cut around the perimeter of your lawn, ensuring that the edges of your lawn are fairly well cut. This works well where your lawn meets a path or a drop, but is less capable where your lawn ends with a wall or fence.

The edge cutting feature has to manually activated and I would recommend doing this once per week or so. Once it has done the edge cutting, it will revert to its normal activities. Overall, I feel that this robot lawn mower is better at managing the edges of your lawn than most other competing robot lawn mowers. However, I still had to manually cut the edges of my lawn with a strimmer every 3 to 4 weeks, to make sure that it stayed neat and tidy.

Limitations Of Mowing Features

Although the Robomow RC304u Has better edge cutting abilities than many other robot lawn mowers, it is still not able to do a perfect job. this is particularly apparent where your lawn meets a fence or wall. the cutting blades are not able to get sufficiently close to cut right to the edge of your grass. for this reason, you will have to do some trimming of the edge of your lawn. however, for most people it will be sufficient to do this approximately every 3 to 4 weeks.

Power And Charging

The Robomow RC304u is powered by a 2.4 amp hour lithium ion battery. It takes between 50 and 70 minutes to charge in the charging station and provides an average work time of 45 to 50 minutes. The average power consumption is 14 kilowatt hours per month. At my local electricity prices, this would cost £2.24 per month.

The lithium ion battery should last for 2-4 years of heavy use and spares are readily available from local dealers and online. There are a few things to be aware of with lithium ion battery technology.

The charging capacity of a lithium ion battery tends to deteriorate when it is stored in hot conditions. After one year in an average temperature of 25 °C, a lithium ion battery will only be able to achieve 80% of its maximum charge. At 45 °C, this drops to only 65%. In contrast, at 0 °C, a lithium ion battery will still be able to charge to 94% of the maximum after being stored for one year.

For this reason, you should think carefully about the placement of your charging station. If you live in a hot climate, placing the charging station in a shady location will significantly extend the life of the lithium ion battery in your Robomow RC304u. 

You could also consider either making or guying a cover or garage for the Robomow RC304u charging station to prevent the robot lawn mower from being exposed to direct sunlight when it is sitting in the charging station. 

While spare batteries for the Robomow RC304u robot lawn mower are readily available, they are quite expensive. You should factor this into the lifetime cost of the Robomow RC304u and take care to look after your battery where possible. 

Maximum Slope

The Robomow RC304u can manage slopes of up to 35% gradient (20 degree slope angle) within the working area of the lawn. This a fair bit better than the McCulloch ROB R1000, but slightly worse than the Husqvarna 310, which are the two main competitors that I would consider for similar sized lawns.

At the edge of the lawn, there are stricter requirements for laying the perimeter wire. You should not install the perimeter wire along a slope of greater than 10% gradient. The reason for this is that there is a risk that the robot lawn mower will slip and cross outside the wire, particularly if the grass is wet.

You may wish to calculate the slope of your lawn before you order a robot lawn mower to ensure that your choice of robot lawn mower will manage to cut your lawn. I have written a guide to calculate the slope of your lawn here.

Movement And Navigation System

The Robomow RC304u was able to navigate around my garden without difficulty. It appears to move in a fairly random pattern around your lawn. It typically moves in a straight line until it meets the perimeter wire, which triggers it to turn and mow in a different direction.

The Robomow RC304u is able to manage to negotiate narrow sections of lawn that are wider than 1.2 metres. If the narrow section is narrower than 2 metres, you have to set the perimeter wire up in a special configuration to lead the robot lawn mower in and out of the narrow passage to avoid it getting stuck.

If you have a passage of grass that is narrower than 1.2 metres, the Robomow RC304u will not be able to negotiate this. You will have to install your lawn as if there were two separate sections of lawn. This is a significant drawback of the Robomow RC304u, and one that has been overcome by a number of other robot lawn mower models. A direct competitor, the McCulloch ROB R1000 can manage to negotiate through sections of grass as narrow as 30 cm.

Safety Features

The Robomow RC304u has a whole host of safety features which ensure that the risk of injury is minimised while it is in use. It has a child lock feature which prevents it being operated by any unauthorised individual. This can be toggled on or off in the settings menu. With it activated, only by pressing two buttons in the correct order, will the Robomow start working.

The Robomow RC304u also has lift, tilt and obstruction sensors. These detect when the robot lawn mower has been interrupted. If the lift or tilt sensors are activated, the blades of the robot lawn mower will stop immediately.

The obstruction sensor will cause the machine to stop and move in a different direction if it encounters a solid obstacle.

There is also an emergency stop button which can be pressed at any time and will stop the blades immediately.

The Robomow RC304u has a power elimination switch which will prevent any functions of the robot lawnmower until this is activated. This is important to use whenever performing any maintenance to the underside of the Robomow RC304u, to ensure the blades do not turn on unexpectedly.

The Robomow RC304u uses sealed batteries that will not leak any type of fluid regardless of their position or storage condition.

It also has very low ground clearance, which means that it would be very difficult to reach under it and come in contact with the blades, without triggering the lift or tilt sensors.

Overall, this makes the Robomow RC304u a very safe piece of machinery. The only drawback that I can see, is that the blades of this robot lawn mower are much larger and more powerful than other robot lawn mowers.

If someone was to come into contact with the moving blades, the injury that they could sustain would be much more significant than from a robot lawn mower that uses an alternative cutting technology. Husqvarna, McCulloch and Gardena, for example, use a number of much smaller, freely rotating blades that will rotate backwards if they contact a solid obstacle, causing much less damage than a fixed blade.

Rain Sensor

The Robomow RC304 has a rain sensor on the outer body of the machine. This sensor is capable of detecting rain or highly humid conditions. If the rain sensor is activated, it will signal to the Robomow RC304 to stop it’s cutting activity, or defer a planned cut. The sensitivity of the rain sensor can be adjusted in the Robomow settings menu.

Overall, I found the rain sensor to be a useful feature. It will be more useful for people with a sloping lawn, where the robot lawn mower might lose traction in wet weather. I have a fairly flat garden, so I didn’t feel the rain sensor provided much benefit in my garden. I experimented with turning the rain sensor off, and I have not seen the Robomow having any difficulties cutting my grass.

Anti-Theft Features

The Robomow RC304u has both an anti-theft alarm and a PIN code feature to reduce the risk of theft of your machine. The alarm can be set to sound when the robot lawn mower is lifted or moved without first inputting the PIN code.

The PIN code prevents operation of the robot lawn mower without first inputting the code. The PIN code can be inputted on the robot lawn mower itself, or via the smartphone app.

Smart Features

Robomow RC304u smart app

The Robomow RC304u comes with Bluetooth connectivity and it has a companion app for smartphone or tablet. This enables you to interact with your robot lawn mower from a distance. You can check a summary of the mower’s progress and see the next planned operation. You can also adjust most of the settings that you can on the physical control panel on the robot lawn mower.

One of the best things you can do with the companion app is manually control the Robomow RC304u and drive it around your garden. This lets you cut any areas of your lawn that need a bit of extra attention or let you drive the mower from one section of lawn to another. I find this to be a bit of fun, but I didn’t find it to have much practical use in my garden. It’s a feature I’m glad they have, as it’s something fun to show people when they visit my house. 

Spares And Repairs

Robomow RC304u spare blades

Robomow have an extensive dealer network which makes servicing and repairing your robot lawn mower very easy. Spare parts are available widely online, and I have no difficulty ordering a replacement blade for my model.

You will probably need to change the main cutting blade of your Robomow RC304u once per year. This is a really easy process to complete. A blade replacement tool is provided in the box with the Robomow RC304u. This allows you to remove the old blade in a matter of seconds without having to physically touch it. The new blade is installed with the same blade replacement tool in a process that does not require you to risk cutting yourself on the sharp blade. It should click into place very easily.

The battery will need replaced every 2-3 years, and you should watch for the cutting time of your robot lawn mower reducing over time, which will indicate that it is time to change it. Due to the modular construction of the Robomow RC304u, it is really easy to change the battery and it can be done in a matter of minutes without any specialist knowledge or tools. There is a great video on Youtube produced by Robomow which shows you exactly how to replace the battery.

My only concern about spares for robot lawn mowers from Robomow is the high cost of them. Compared to other comparable robot lawn mowers, the spares are quite expensive. Certainly, everything is high quality, but I think the batteries in particular are more expensive than they need to be.  


Robomow offer a 2 year warranty on the Robomow RC304u which I think is quite reasonable. Any major defects are likely to surface within two years. Outside of the two year warranty, repairing the Robomow RC304u is generally very easy and can be done through the Robomow dealer network. If you look after your Robomow RC304u well, I see no reason why it could not have a lifespan of at least 10 years.


Overall, I think the Robomow RC304u is the best robot lawn mower available for lawns of between 600 m² and 1000 m². There are a number of caveats to this recommendation.

If you have a complicated lawn, the Robomow RC304u may not be able to achieve coverage of 1000 m², so you may wish to opt for the next Robomow model up, the RC308u, or go for either the Husqvarna 310 or McCulloch ROB R1000.

The Robomow RC304u also isn’t the cheapest robot lawn mower that can manage a lawn of 1000 m². That honour goes to the McCulloch ROB R1000. This is also a really good robot lawn mower, but lacks a few features and has less slope ability than the Robomow RC304u. If you have a very flat lawn and don’t mind doing without the smart features, the McCulloch ROB R1000 offers great value for money.

Robomow RC304u Robot Lawn Mower Review









  • Sleek design
  • Excellent lawn edge cutting ability
  • Turbomow mode makes light work of longer grass
  • Excellent dealer network for spares, repairs and installation if required


  • Louder than comparable robot lawn mowers
  • Greater power consumption than comparable robot lawn mowers
  • Some uncertainty about lawn size it will handle