The RX20u is the smallest and most affordable model Robomow have ever built. It is best suited to those with small gardens (between 200 – 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 others.

Now even though it is smaller and cheaper, the RX20u still has the great mowing features that you would see on Robomows bigger and more expensive models.

Such 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 lawn make sure you stick around as I’ll be reviewing all of its features, functions and capabilities.

Main Features:

  • Rating: 9/10
  • Covers Areas up to 300m² (preferably 200m²)
  • Hard to Beat Mobility
  • Mobile/Tablet Connection
  • Easy Operation

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

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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 9/10 7/10 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°.

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 time then you could be left waiting up to 20 HOURS for it to fully recharge.

Considering the size of lawn it’s designed for the RX20u shouldn’t have a problem finishing lawn in one go but I have to say I was a little shocked when I seen 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 2018.

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 levelled with you 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 lift it from one to the other, as long as there 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 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.

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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 purchase. If you have any areas of lawn which are narrower than this then the RX20u will not even be able to pass through here, 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 lie 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 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 kinda 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 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 gardens health and so you don’t have collect all those pesky clippings, the RX20u cuts your grass into small pieces.

So small in fact you that 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 work to operate differently.

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

Turbo Mode

The Robomow RX12u 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’. So 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 mow.

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.

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Safety Features

Bump Sensors

Okay so you probably have some garden accessories in your lawn like chairs, potted plants and trees. Well wouldn’t it be a shame it 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. 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 trimmers out once in a while.
  2. For the Bluetooth connection to work you need to be standing quite near the mower so you can’t control it from your couch.
  3. 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 this in one go.

So 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, I am really impressed with the RX20u.

For such a small mower you are get so much value and I think an appreciative hat tip to the folks at Robomow is in order.

From what I have seen the RX20u has definitely out done its competition.

Features like the Floating Deck and the Glider really do make this perfect for the small, complex garden. And not only that but things are included that you usually only find on a high end model – like the mobile connection and multi-zone feature.

If you have a small and are in the market, then I recommend you make this your first choice!

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

Hopefully these pointers have made it clear if you’re suitable for the RX20u. This really is a great mower and if you have the garden for it, I know you’ll love it! If you want to check out the latest prices make sure you go to eBay.


Where can I purchase this model?

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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

Last update on 2019-09-21 / Affiliate links / Images from Amazon Product Advertising API

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Robomow RX20u
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