Replacing a Husqvarna 450X with an Ambrogio 4.0

Some background

We moved into our house about 5 years ago.  One of the main reasons for moving houses to have a bigger garden so our new house came with 4 acres of which 1.5 acres is grass that needs mowing. It’s split into a number of areas some so we bought a sit on mower to augment our petrol mower.

Initially the thought of driving round the garden on the sit on mower listening to music seemed appealing however, the reality turned out to be somewhat different. The mower kept breaking down, the ground was too soft for the mower to mow the grass early in the season, sitting on a mower for three hours at a time was hot tiring work, it was noisy, it kept scalping the grass (some areas are very uneven) etc. etc.

The solution could have been to buy a better sit on mower or pay someone to do it but neither of those options seemed appealing so I started researching robot mowers.  I discounted most mowers as they could not cope with the large area we wanted to cover and in the end settled on the largest Husqvarna (the 450X).

Our Garden

Our garden consists of a number of interconnected areas as you can see from the aerial image.  The areas in red is what we decided to run the mower on an area of approx. 4000 sq. m.

We excluded the area in yellow as it would require the robot to cross the driveway.  This is possible but one I would never recommend as in a battle of car versus mower, there can always only be one winner.

Our Garden

The excluded the areas in blue as these are surrounded by a wall and hence have no access from the red area.  We now run Ambrogio robots on these areas (an L35 and a L60)…more on that later.

The 'bridge' that links area 4 & 5 (d on plan)
View of area 2 on the plan
View of area 6 on plan
Trees in area 5

Installation of the 450X

The 450X was installed on a wet and miserable day by our local Husqvarna dealer.  We sited the base station near where we had power and where we thought it would be out of the way (more about that later).  

Looking back on this, I would always recommend installing a robot mower on a dry day for a couple reasons:

  • The practical reason is that the wire laying machine needs to grip the grass so if the grass is wet, it makes the job harder
  • The psychological reason is that you will always make a better job when you are not cold, wet through and trying to catch up time that you’ve lost because of the wire layer slipping.
Installation of the 450X involves:
  1. Laying the perimeter wire – basically following the red line on the garden plan
  2. Laying up to 3 guide wires which allow the robot to navigate to the edges of the areas.

About 1km of wire was used in the installation.

Husqvarna 450X

Living with the 450X

After a few weeks of sorting out rabbit holes, moving wire where it was not quite in the right place and ‘hiding’ it from passing footpath users (hence the sleepers in the photo), things settled down.  On the whole it just got on with it’s job, it got stuck every now and then (unfortunately mostly when we were away on holiday).  The app tells you where it is stuck, a useful feature, but there is not a lot you can do about it if you are on holiday.

There are just a few ‘niggles’ that we had with it:

  • Build quality – the cover feels cheap and marks fairly easily….having said that, it hasn’t caused any issues yet.  You can see a video that goes into more detail.
  • The unique cutting blades that swivel back when they hit something are good in theory, however it you have branches, fallen apples etc. you sometimes want something that is a bit more aggressive.
  • The lack of control that you have on which area it mows.  We like the lawn at the back of our house to be the best cut (as we see it all the time) but the schedule does not allow you to control where it goes or be able to send it to another area.
  • The wire was still on the surface on the lawn in a number of places.  This was due to a mixture of a hurried installation and the very dry summer which meant the grass did not grow over it.
  • Tracking issues. When a mower follows the same route time and again, the grass in that area tends to wear more than others and you end up with tracks.  We now have areas where the grass is browner as the mower follows a small number of paths when it exits the base station…and when it tries to find the base station.  This has been made worse by the dry summer we had last year. See photo.
Tracking Issues with the Husqvarna 450X

The end of an era - removing the 450X

In some ways the Husqvarna became a victim of it’s own success.  We had numerous friends who came over and said that they had never seen a robot mower before or didn’t realise that it could handle large complex gardens.

We started looking at the possibility of setting up a company to sell and install robotic mowers in our local area. Having looked at various makes, we settled on Ambrogio as it offered a larger range of robots than Husqvarna and could cope with much larger lawns.  It was also had an expanding dealer network with no coverage in our local area….The Robot Mower was born.

I think that any robot mower dealer should have first hand experience of using them so one of the first jobs was to replace the Husqvarna with a Ambrogio 4.0….it looks like a robot (or a tank at least)!

We spent some time looking at the possibility of running the Ambrogio using the same perimeter wire as the Husqvarna, in the end we decided that it wasn’t the best solution for a number of reasons:

  • The Husqvarna perimeter wire is not as thick and resilient as the Ambrogio wire. 
  • The perimeter wire had not been laid as close to the lawn edge as possible which meant that larger areas had to be strimmed/ cut manually.
  • It gave us experience of laying a large amount of wire on a complex lawn using our new wire laying machine.
  • It allowed us to use some of the advanced Ambrogio specific techniques to improve the robot navigation/ performance.
Removing the 450X was as simple as disconnecting the base station and removing the visible perimeter and guide wires…or at least we thought.  With 1km of burried wire, it’s difficult to find  and extract all the wire.  One reason why I now take a video following the perimeter wire after an installation making a note of spare wire, joins etc.

Installation of the Ambrogio 4.0

We decided to locate the base station in a different area which offered protection from prying eyes and was located on the lawn that we wanted mowed first.

We decided to tweak to mowing areas: 

  • We removed an area which required us to open a gate to ‘let the mower out’…as we never did this so it was always cut manually. This is now cut using our L35 as a closed area i.e. twice a week we pick up the L35, walk 10 meters, drop it in the area and 60 mins later it’s mowed.
  • We trimmed edges so that we could lay the wire as close as possible to the edge and hence minimise the manual cutting
  • We expanded one area as we thought that the 4.0 would be able to cope with the uneven ground where the 450X had struggled.
Ambrogio 4.0 base station
Base station relocated
Area that a 450X struggled with
Expanded area

The Ambrogio robotic mowers navigate to areas of the lawn in a different way to the Husqvarna.  They follow the perimeter wire either clockwise or anti-clockwise for a given distance before starting cutting. This makes it easy to define new areas…you just add them to the app.

In order to minimise tracking issues, Ambrogio have a specific technique that allows the robot to follow the wire but stay a varying distance away (up to 1m.). This works well but requires a bit more planning as if you have a passage less than 1m it could skip it.  To get around this issue, you can put in ‘recall to wire’ points to allow the robot to follow the wire through tight spaces/ passageways.

Living with the Ambrogio 4.0

The first issue we hit was that the mower would not come out of the base station correctly…pretty major but after some investigation we found that the signal from our other mower was interfering with it.  Swapping the channel that it was transmitting on solved the problem.

The next stage was tweaking the setup to ensure that all the lawn was mowed with as few areas being setup as possible and that we had a few recall to wires as possible. Having not used the recall to wire before and having lots of curves before and after the recall to wire it was a bit of trial and error but I can say that I have now mastered it.

We were a bit worried that we had tried to push the edges a bit too far and that it might not cope with the uneven expanded area but the 4.0 has coped very well, the pivoting body allows it to cover areas that the 450X would not have coped with and the cut is more even than with the 450X.  All in all a good start.

Play Video

Cutting among The Trees

Ambrogio 4.0 Pivoting Deck
Play Video

The 4.0 pivoting deck

Play Video

The 4.0 in a spiral cut

Robot Eye View
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A robot’s eye view

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