Robomow RX20u Review

Gtech Lawnmower Black Friday Discount

Update March 2020

Please note that Robomow has introduced a new model called “Robomow RX 50u Connect” that will be available on the UK market towards the end of March 2020. This new robotic mower is equipped with the latest Lithium-ion battery technology and other enhanced features. I would therefore recommend that you do not purchase the Robomow Rx20u and RX12u due to its older technology, including the Lead Acid battery. If you are looking for a robotic mower of this size I would strongly recommend the WORX WR130E S300 OR wait to my full review of the new Robomow RX 50u (I will complete this review when available). The WORX WR130E S300 is packed full of the latest technology, and is my number 1 recommendation for lawns up to 300m².


The RX20u is the middle brother to the range of RX Robomow models. It is best suited to those with small gardens (between 200m² to 300m²) that are shaped a little more complex than most.

Because of its very smart navigation and mobility, the RX20u can handle these gardens much more effectively than other makes/brands.

The RX20u still has the great mowing features that you would see on Robomow’s bigger and more expensive models. For example, the floating deck, mobile/tablet connection and the various mowing modes you can choose from.

Considering everything that this model is equipped with, it is very difficult to match how much value the RX20u provides.

But to see if it belong in your garden make sure you read on as I’ll review all of its features, functions and capabilities.

Main Features

  • Rating: 7.5/10
  • Covers Areas up to 300m² (preferably 200m²)
  • Hard to Beat Mobility
  • Mobile/Tablet Connection
  • Easy Operation

Robomow RX20u Video

To get a glimpse of what the RX20u is capable of, watch the Robomow video below:

Check Today's Price

Model Comparison
Mowers Robomow RX20u Flymo 1200R Husqvarna 105
Lawn Coverage 300 m² 400 m² 600 m²
Noise Level 63 dB 58 dB 58 dB
Mowing Time 90 – 120 minutes 75 minutes 70 minutes
Charging Time 16 – 20 hours 60 minutes 50 minutes
Dimensions 53x42x26cm 58x46x25.5 cm 55x39x25cm
Weight 7.5 kg 7.4 kg 11.1 kg
Mobile App Yes No No
Slope Capability 14° 14°
Rating 7.5/10 9.4/10 9/10


As I have already made clear, the RX20u has exceptionally good mobility, but why exactly is that? Well it comes down to a few things…

robomow RX20u topSmart Mow

Because of Robomows Smart Mow technology, the RX20u mows without any interruptions, produces a precise cut and can cover your garden much more efficiently than other competing models (up to 10% faster).

However that is not enough to handle a complex garden, with many small spaces and narrow passages.

That is why Robomow have made the RX20u much smaller and compact than any other of their models. With this design it can squeeze through even the tightest of angles.

Giving it a better chance of covering every inch of your garden.

And it can also travel along gentle slopes reaching 8.5° – which isn’t the best if I’m honest, the majority of robomowers can reach up anywhere between 20 – 22°.

This may not be an issues but just make sure to keep it in the back of your mind before purchasing.

Driving System

Again this is slightly different from most models but just like above, it actually improves the mobility of the RX20u.

Instead of making use of the standard three wheels, Robomow have went with something a little more innovative.

Just like all Robomow models, it uses two big wheels at each side so that is stays balanced and steady. But instead of using a typical third wheel at the back, the RX20u has been fitted with a Glider.

This promotes better maneurverability as it gives the mower much more freedom and allows it to make turns with ease. Making it perfect for complex gardens.


Power System

The RX20u mower is powered by a Lead Acid battery and electrical motor to produce between 90 – 120 minutes of mowing time.

For such a small mower this is pretty good and it should finish your lawn within this time, however it has a downside…

If it doesn’t finish the lawn in this time then you could be left waiting up to 20 HOURS for it to fully recharge. This is due to the mower being fitted with the older Lead Acid battery.

Considering the size of lawn it’s designed for the RX20u shouldn’t have a problem finishing your lawn in one go, but I have to say I was a little shocked when I saw this.

The reason behind such a poor charging time will be the fact that the mower makes use of a Lead Acid battery, these are less efficient than the much more common Lithium-Ion battery seen in all robomowers (or at least all the ones I’ve seen anyway).

Other than not being able to develop one to fit the RX20u, I can’t think to why Robomow wouldn’t fit this model with one.

I’d imagine this will be quite a turn off for most people and is definitely something they’ll need to work on going into 2020. (New Robomow RX 50u Connect model will be released in the UK late March 2020 – it has all the new features, including the latest Lithium-ion battery).

robomow with base stationMowing Features

Floating Deck

The Floating Deck feature allows the blade to move up and down with the slope of the ground. Meaning the RX20u can stay level with your garden, reaching every inch of grass.

So whenever the mower comes across any bumps or holes while on route, it will be able to cut it just as evenly as flat land.

Multi-Zone Feature

So that this model can take care of a whole range of complex gardens, like all Robomow mowers, it can travel between separate lawns (5 of them).

There’s no need for you to lift it from one to the other, as long as there is a passage of some sort it can make its own way there.

However you will need to make sure the perimeter wire surrounds all lawns and that the passage is not too narrow (see user manual for exact measurement).

This shouldn’t make the installation process any more difficult but I guess that depends on your lawn. And even if it is, this saves you the effort of dragging it from one area to the other. So I think it will be worth your time anyway.

Rain Sensor

The RX range of robotic mowers do NOT come with a rain sensor. Rain sensors are found on the RS and RC Robomow robotic mowers.

Check Today's Price

Narrow Paths

In order for this mower to work properly around your lawn, you need to ensure that there is at least 15cm of space between one length of perimeter wire and another.

Just make sure you keep this in mind before your purchase. If you have any areas of lawn which are narrower than the RX20u will not be able to pass through, never-mind mow it.

Robomow App

Robomow AppTo limit your interaction with the mower and to make your life just that little bit easier, the RX20u can be controlled by your phone or tablet.

So whether you’re at work, out on a jog or enjoying that lay in on a Sunday, you can send the mower out to work.

Of course that is not all it can do. As with any mower you are going to need to make changes to mowing route, schedule and cutting height so for convenience and ease of use the app lets you do that too.

And for those tough little spots in your garden that are proving to be too difficult for the mower to handle, you can do it yourself, and I don’t mean physical mowing.

Just like a toy car you can control the RX20u with your phone. I know this is still technically you mowing your lawn – which sort of defeats the purpose of a robomower – but sometimes the mower just needs your help.

And I think you’ll agree that this way is better than physically mowing!

The RX20 is also equipped with a GSM module which prevents faults and minimises downtime of the mower. It collects technical data from the mower and then sends you operational and security alerts to your phone accordingly.

Keeping you up-to-date with everything you need to know about your RX20u.

Robomow RX20Blade

The RX20u is equipped with a slightly different blade than other Robomow models. It is a little smaller and only has two edges, probably to account for its smaller size.

But don’t worry it is still just as effective.

Built strong and tough, this blade gives you a flawless cut and will only need to be replaced once a season, saving you time and effort.

And as I mentioned earlier, you can adjust its cutting height (between 15-45mm) for the changing seasons.


For the benefit of your garden’s health and so that you don’t have to collect all those pesky clippings, the RX20u cuts your grass into small pieces. So small in fact that you cannot see them after mowing because they have fallen all the way down to the bottom soil.

This is where the magic happens.

The clippings will begin to decompose and act as a fertiliser (mulch), providing nutrients for the soil to improve its growth and overall health. This results in a much fuller, greener and better looking lawn.

So not only will the RX20u maintain your lawn, but it will also improve it as well.

Mowing Modes

So that the RX20u can fit into different environments and adapt to different situations, you can program it to operate differently.

This is done through a selection of gardening modes, which I will explain in more detail below…

Turbo Mode

The Robomow RX20u does NOT have the Turbomow feature. This feature can be found on the RS and RC models.

Eco Mode

So that the RX20u operates using minimal energy for cutting your grass and maintaining your garden, you can set it into ‘Eco Mode’. When you want to save a little bit of energy this feature is ideal.

However be warned this does slow down the RX20u work rate so it will take longer to finish the mowing.

Edge Mode

Now this is the most useful of all modes – the ‘Edge Mode’. This program instructs the RX20u to follow the perimeter wire and cut only the borders of your garden.

Giving it a chance to reach and cut the outer limits of your lawn.

However the problem is still not quite solved yet.

If your garden is next to the wall of your house or a fence, the RX20u can still not cut the grass beside it. So after every mow, you will have to go out with the trimmers and clean this up.

This can be quite annoying but I think it’s more than a worthy trade for mowing the entire lawn yourself.

Check Today's Price

Safety Features

Bump Sensors

Okay so you probably have some garden accessories on your lawn like chairs, potted plants and trees. Well wouldn’t it be a shame if your brand new mower ran off course and started eating these.

I think you wouldn’t be best pleased and you’d probably want a refund – I would too.

Well no need to worry the RX20u comes with its own bump sensors.

So whenever it comes into the slightest contact with any of these obstacles, it will stop immediately and turn off its blade, recalculate a new route to follow, move backwards a couple of spaces and turn to mow in a different direction.

Keeping everything – including and especially you – safe when it’s away at work.

Lift & Tilt Sensors

The RX20u is equipped with sensors that turn off the blades immediately when the mower is either lifted or tilted. So if you need to replace or clean the blades, don’t feel scared or cautious, you will not be in harm’s way.

Although if you can be a little overcautious at times (like me) then lift from the back of the mower. This is furthest point away from the blades and there’s a handle to grab hold on.

PIN & Alarm System

To protect your mower from being stolen and so that others can’t use it unauthorised, the RX20u comes with a PIN code.

If handled or played with without the code then an alarm will sound and (if you have connected to the app) a notification will be sent to your phone.

The mower also comes with a Child Lock to prevent anyone unfamiliar with safe operation from operating it freely.


  1. Old battery technology.
  2. Because of the mowers shape and the size of blade, it can’t reach grass beside a wall or fence. This means you’ll have to get the trimmer out once in a while for that perfect edge to edge finish.
  3. For the Bluetooth connection to work you need to be standing quite near the mower, so you can’t control it from the comfort of your sofa.
  4. The Charging time of 16 – 20 hours is a very long time to wait before the RX20u can get back to action. But considering the size of lawn it is built for it should finish mowing your lawn in one go.

In summary, there isn’t all that wrong with the RX20u if you compare it to other models. This model has so many good qualities that having a couple of flaws is more than acceptable

Robomow RX20Conclusion

As you can probably tell from my tone just above, in 2017 I was really impressed with the RX20u. However things and technology has now moved on and there are much better alternative robotic mowers available on the market today.

If you have a small garden and are in the market, then this model could be an option for you, however I would strongly recommend that you wait for the new Robomow RX 50u Connect (will be released late March 2020) or consider the new WORX range of robotic mowers – these are my top picks due to their features, value for money and performance. 

Should You Buy This Mower?

Even though this is a great mower, it doesn’t fit everyone’s garden. So to help you understand whether or not it deserves a place in your garden and if you’ll take full advantage of its features, run through the garden factors in the list below:

  • Your garden is not larger than 300m²
  • Your garden is complex in shape so will make use of the RX20u mobility
  • Your garden is separated between 2 – 5 lawns that are connected to one another via a pathway
  • Your lawn has slopes under 8.5°
  • You will make full use of the Robomow app
  • You don’t mind doing a little bit trimming every now and then
  • Someone who doesn’t mind longer charge time 16 to 20 hours

Hopefully these pointers have made it clear if you’re suitable for the RX20u. Please see my March 2020 update at the top of this review. There are other more suitable options available on the market at the moment with latest technology (this model is now too dated and less efficient compared to other models/brands).

If you want to check out the latest prices make sure you click on the link below to see the latest price.


Where can I purchase this model?

Check Today's Price



Additional Specifications
Working Area 200 – 300 m²
Max Incline 8.5°
Battery Type Lead Acid
Battery Power 26V
Mowing Power 100W
Typical Charging Time 16 – 20 hours
Typical Mowing Time 90 – 120 minutes
Cutting Height (min-max) 15-45 mm
Cutting Width 15-45 mm
Sound Level ECO mode: 64 dB Measured – 67.9 dB Guaranteed – 69 Db
No. Of Zones 5
Alarm Yes
PIN Code Yes
Rain Sensor Yes
Floating Deck Yes
Lift Sensor Yes
Tilt Sensor Yes
Perimeter Wire 100m or 200m
Product Size LxWxH 53x42x26cm
Weight 7.5 kg
Lawnmower Product Expert, Reviewer and Author at | 01284 615144 | | Website | + posts

As a seasoned expert in the field of garden power tools, I have dedicated over a decade to working with and reviewing a wide variety of lawn mowers. My extensive experience has allowed me to gain a deep understanding of the benefits and limitations of different types of mowers and garden tools.

Over the years, I have honed my skills in writing informative articles and creating helpful videos for various blogs and publications. This has given me the ability to not only recognise what makes a good lawn mower, but also to help you choose the perfect garden tool for your specific needs and requirements.

With my wealth of knowledge and expertise, I am confident that I can provide you with valuable insights and recommendations when it comes to selecting the right lawn mower for your lawn. So, whether you're looking for a battery cordless, electric, petrol, or robotic mower, you can trust in my expertise to guide you towards the best option for your garden.

6 thoughts on “Robomow RX20u Review”

  1. The long charging time is because they are still using the old style lead acid battery as is clear on their website. Bit of a game breaker.

    1. Wow I could’ve swore they used a Lithium-ion battery, the poor charging times make more sense now. Maybe they could make the battery small enough to fit in the mower, hopefully they’ll make some advancements going into 2018.

      Thanks for pointing that out, I’ll make a change to the review where required!

  2. I have never seen such a small “robot mower” before. It is very cute. Even though it is too small for my garden It is something to think about in the future when I get older or just too busy and my lawn has a little more bushes and flower beds. What a great idea!

    1. Yeah i think it’s a great little mower and perfect for those with smaller gardens.

      If your lawn is too big then why not check out some of the robot mowers I’ve reviewed that are built for a bigger areas. You can check them out here on my home page.

      Thanks for the comment and this helps you find a suitable mower ;-)

  3. Jan Soetendaal

    Hi Easy Lawn Moving, I saw your Robomow RX20 Review. Impressive to see in the video how the robot works. One question does I have about the charging.
    I read that the charging time is of the Robomow RX20 is much longer. Do this mean that the energy costs are higher? Regards, Jan

    1. Hi Jan, yeah Robomow have made a really good job of it. Even though it does take a while to fully charge the battery, I think it doesn’t cost you any more money, it’s just not the most efficient system by the looks of things.

      So you shouldn’t need to worry about spending more than you would with other mowers.

      Thanks for the comment and if you have any other questions then just let me know ;-)

Leave a Comment

Your email address will not be published. Required fields are marked *

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Protection Status

As an Amazon Associate I earn from qualifying purchases. is a participant in the Amazon Services LLC Associates Program,
an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to,,
and any other website that may be affiliated with Amazon Service LLC Associates Program.

Scroll to Top