I was motivated to write a review of the new Lidl Parkside 20V robot mower with 1000m2 of coverage. The model number is PMRDA 20-Li A1. I have always wanted a robot mower, but I was not convinced they would work well in my garden due to all the pine cones. They are also very expensive as you move up the range to the models that support larger gardens. My garden is split in two by the parking area which is gravel and I was going to have to re-design my garden and put in a grass strip to join the two lawn areas which I really didn’t want to do. Robot mowers generally don’t like crossing gravel areas and I didn’t want the mower to get hit by a car. A local agricultural machinery store came out and did a survey of my garden and suggested the Husqvarna 450x model which was going to cost over 5000 euros plus a yearly maintenance charge where they would service your mower and upgrade the firmware. I don’t know if the yearly service charges are still recommended with the newer Husqvarna models.
One of my lawn areas is about 450m2 and the other is about 900m2 and it took me about two and a half hours to cut the grass with my 21inch power drive Honda lawn mower. I collected the grass in the smaller lawn area and didn’t bother in the larger lawn area or it would add another half hour on to the time. I generally cut the grass every other week due to the time it takes and only when the grass is dry.
I was thinking about getting a ride on mower, but I don’t really have the space in the shed. I then saw that Lidl were bringing out a 20V robot mower for 350 euros that was compatible with all the 20V battery tools. I took a chance and bought two of them to cover each of my lawn areas. Lidl have a policy that you can return them and get a full refund within 28 days of purchase, so I figured it was worth a try.
In the Box:
The mower includes a base station with power supply and ground spikes, 200M of boundary wire and 350 pegs to fasten the cable to the ground. The new model has doubled the range of the older model that covered 500m2 to 1000m2. The older model came with the smallest 2Ah 20V battery and the new model comes with the larger 4Ah battery.
Planning your install:
I suggest you use the measure distance feature on google maps using the satellite view to plan your installation. This will allow you to work out the approximate area of lawn that needs cutting and also allows you to work out how much boundary wire you will need. Always allow for obstacles like trees and septic tanks and so forth. The manual states not to go over the 200M of boundary wire, so allow for this when planning your installation. The mower supports creating islands around trees with the boundary wire in you lawn. This was not very clear in the manual as the pictures suggest leaving 10CM between the parallel boundary wires when you create your island. With a 10CM gap between parallel boundary wires, the mower will overshoot the wire on each side and the grass in the middle will be cut before stopping. However, It will not drive over both wires when 10CM apart. I wanted my mower to drive over the two parallel boundary wires running to the island. This was achieved by running the cables right beside each other and using the same pegs to secure them to the ground. Most robot mowers that use a boundary wire support this feature but it can result in problems. The problems arise when the mower needs to follow the boundary wire to return to the base station to recharge and it hits the island you have created. Depending on the model, this can result in the mower making endless circles around the island as it tried to return to base and your battery will be rundown leaving the mower stranded. I am pleased to say my Lidl robot mower went around the islands I setup for 1.5 to 2 turns and then went in another direction before finding the boundary wire and returning to the base station to recharge. Both islands were irregular shaped and they measured 8M and 14M in circumference. Remember to never cross your boundary wire when making islands.
Make sure you leave at least 2M of slack cable beside where the base station is to be installed as you may have to adjust it before you start running the cable. The manual suggests leaving 2M of straight line space at the end the mower enters the base station and and 1M behind it. It is very important to orientate your base station in the correct direction when planning your install. The boundary wire generates a magnetic field the mower picks up to operate and it will not work at all if you have your base station pointing in the wrong direction. This crucial step is not well documented in the manual and I had my base station in the wrong direction when I first set it up before I realised my mistake. You will know when you have it wrong when the mower immediately tries to make a circuit of the boundary wire when you do not have any secondary zones set. It will generally get lost or stuck and will not cut. Make sure you orientate your base station so that the mower always returns to the base station in a clockwise direction. Swapping the boundary wire around in the positive and negative terminals will not work as the mower will try to return to the base station to recharge in the wrong direction and will hit the back of it. My neighbour made the same mistake and was going to return it as non functional after a day of frustrating trouble shooting before asking me to take a look for him. I suspect Lidl will get many returns as this has not been made clear. There is a diagram on the base station showing this, but it is easy to miss.
The boundary wire can be buried up to a depth of up to 5cm or you can peg it down. I simply pegged the cable to the ground as you can make adjustments later on if the mower gets stuck on the boundary. I strongly suggest mowing the garden with your regular mower first with a tight cut and picking up the grass. This makes installation of the boundary wires much easier. I was very generous with my pegs and used one every 60CM in straight lines and closer again around obstacles. I made sure the cable was reasonably tight and that I could not easily get my fingers underneath it. If your lawn is uneven like mine, I recommend putting in a peg in every hollow to ensure no gaps beneath the cable. If you can get four fingers underneath it, the mower can cut it. I found the pegs would not always go in straight due to stones in my lawn and sometimes this resulted in the boundary wire going in at a slight angle when running a straight line. Try and avoid this if possible as I noticed the mower would pick up the slight change in angle and change direction slightly before correcting itself. This isn’t that much of an issue but I have noticed it really slows the mower down when it returns to the base station which can add time when you have a long boundary wire. The mower goes much faster in straight lines and really slows down at corners and when you run the boundary wire around the base of trees and bushes. The larger of my lawn areas is long and thin and I set a secondary zone on the mower to follow the boundary wire for 80M before starting to mow. The mower takes about 10 minutes to travel the 80M and there are approx 5 corners and 3 trees to avoid on route. Also, pay special attention to avoiding 90 degree angles as the manual suggest and go with 2 x 45 degree angles instead. The mower does not like running the boundary wire on slopes and the manual recommends to not lay the boundary wire on a slope of 10% or more. The reason for this is the mower returns along the boundary wire and drives straight down the middle. I found my mower slipped a lot when returning on slopes and went out of bounds several times. I simply moved the boundary wire up to where there wasn’t much of a slope and had no problems after that. The mower will drive up and down steeper slopes, but they can’t be near the boundary wire due to the mower turning when hitting the boundary. Make sure to remove protruding roots or rocks or run the boundary wire around them.
Remember you will use up your boundary more quickly if you run it around obstacles. This means less of a working area. I have let the mower bump off sturdy trees to save on boundary wire and increased the working area as a result.
In summary, play it safe when running the boundary wire and make sure you follow the instructions to leave at least 30CM between the boundary wire and the sides of your lawn and 40CM at the bottom of slopes. You will always have to strim areas of the garden or cut small areas if your lawn boundary is on a slope like in my case. The mower will cut the lawn in most of your garden and it’s not worth running the boundary wire closer to your lawn boundary than the 30CM or 40CM in the hope you will never need to strim or mow again. The robot will get stuck and you will get frustrated with it.
Running the mower
Once you have your boundary wire correctly setup and you have power running to your base station, you can set it up to mow. The menu on the top of the mower is very simple to follow and you can setup a weekly or daily schedule. The schedule allows you to programme two mowing slots per day. You also need to setup the operating time and the manual has a guide with suggested operating times based on how many metres squared your lawn is (1 hour – 24 hours a day). As I referred to above, the mower has a useful feature that allows you setup several secondary areas for your lawn. This is particularly useful if your lawn is a complex design as you can program the mower to follow the boundary wire in an anti-clockwise direction for a set number of meters before entering a percentage of how much time to spend there. The mower will still operate in random directions when it gets there.
The mower has a rain sensor and will return to the base station if it starts to rain. There is a feature that will make up for lost time if it cannot run for the number of operating hours you have setup due to the rain. This feature can be disabled and the mower can operate in the rain. However, you are better off leaving it on as it’s best to cut the grass when dry.
There is an app for the mower, but you will need an external wireless access point to use this that covers your garden. I didn’t bother with this as there is nothing you cannot set directly on the mower with the menu. If the mower gets stuck, the app will notify you. I simply look out a window instead. There are several reviews on YouTube for the mower that run through the menu and app but I didn’t find any in English yet. There are subtitles on some. The best one in my opinion is the following. It is in French with English subtitles.
https://www.youtube.com/watch?v=D5D4x6Q-Umo
Trees, Fallen pine cones and apples
The manual recommends you run the boundary wire around trees. I would say this is necessary for smaller trees and bushes, but it can use up a lot of your boundary wire if you have a larger area with many obstacles. For larger trees, you can allow the mower bump off them. The manual claims the mower has a sensor that is able to detect and evade stationary obstacles. I have found this is not the case, and the mower will bump into the solid object like trees of any size if they are not surrounded by the boundary wire. The mower is designed to take the bumps though and I don’t believe it will cause any harm.
One of the main reasons I held off in buying a robot mower was my uncertainty with how it would handle pine cones and apples. I have several Scotts pine trees in my garden which results in thousands of pine cones falling on to the lawn in various sizes each year. The pine cones used to sometime fall on their ends when the grass was long and they could be more than 6cm in length. The width is generally less than 5cm though. When I used to cut the grass myself, the grass would grow long and it was hard to spot them. The first thing I did was rake them up before running the robot mower for the first time. The pine cones that fall on my smaller lawn area are smaller than the pine cones that fall on my larger lawn area and I set my cut height to 45MM on that lawn. The grass will always be cut to this level which looks quite tight and the pine cones always fall on their sides as the grass is short. This means the mower will most often drive over them without cutting them which would result in blunter blades and more frequent blade replacement. The other benefit is they are very easy to see when the grass is short and it doesn’t take long to pick them up each day if you chose to.
For my larger lawn area with the bigger pine cones, I set the cut height to 55MM and it drives over most of them. I don’t see it working for falling cooking apples as they can be much bigger and it would ruin the fruit. I simply did not run the boundary wire close to the apple trees for this reason.
I have included a picture showing the pine cones on a level service beside the mower for reference.
Multiple Zones
For my larger lawn area, I used all 200M of boundary wire as I used up a lot of wire running it around the septic tank and some smaller trees and bushes. The mower runs perfectly. I wanted to push the boat out and see if it was possible to extend the boundary wire past 200M as the manual states that 200M is the limit. I installed an 8Ah 20V battery in the mower in my larger lawn area which theoretically doubles the battery life between charges and would also increase the operating time. I did not want to change my existing boundary wire layout, so I used some of the boundary wire left over from my smaller lawn area to extend the lawn area to mow. I installed a 12V waterproof switch at the point I extended the boundary wire to create a larger loop and a waterproof gel connector with 3 cable inputs at the other join area. I followed the instructions as described in the following post.
https://www.reddit.com/r/worxlandroid/comments/hrbbrl/splitting_zones_by_toggle_wire/
The diameter of the included boundary wire cable is approx 2.7MM including the green insulation and approx 1.09MM for the copper/aluminium core. Now it will be possible to extend the boundary wire with no problems beyond 200M if using a heavier gauge wire as there will be less resistance over longer distances when compared to the boundary wire included. Most people will use the included boundary wire like me though. I measured the resistance of the included boundary wire using a multi meter in both my lawn areas before making any cuts. The wires were continuous at this point with no joins. The resistance of the included boundary wire over approximately 94M was 3.7 ohms and the resistance over 200M was 6.9 ohms. I added another loop extending the boundary wire on the larger lawn area by another 23M. The resistance on the original 200M of boundary wire after installing the switch was unchanged at 6.9 ohms and the resistance on the extended 223M boundary wire was 7.7 ohms. There is very little in the difference and the mower appears to be working perfectly with the larger loop. There will be a limit of acceptable resistance before the mower will stop working in wider open spaces with a loop error message. I can now easily use the switch to turn on and off the new area to mow. I am going to use the same switched technique to create islands around groups of daffodils when they come up in the Spring which will further extend the boundary wire and perhaps even for the Apple trees in the Autumn when the apples fall.
I purchased this three position switch to turn on and off the extended boundary
https://www.amazon.co.uk/dp/B09TFN959N?psc=1&ref=ppx_yo2ov_dt_b_product_details
Power consumption and battery life
The base station rated power output is 2.5 amp. I used a digital power meter to measure the power consumption over a week for my larger lawn area. I ran the mower for 12 hours operating time each day which was equal to two charges for the 8amp battery. The power consumed was approx 2.6Kwh for a week which was equal to about 1 euro of charges in Ireland at our rip off rates. I have a night meter, and one charge per day was at night rates (.46 cent day and .23 cent night per Kwh inc VAT). The mower returns when the battery falls to 30% capacity. The base station consumes 2-4 watts of power when the mower is out mowing to provide a charge to the 200m of boundary wire. The 4Ah battery takes about 1hour 20 mins to charge and the 8Ah battery takes about 2 hours to charge.
I have found the battery life to be much better than stated in the manual. The manual states the 4Ah battery mowing time lasts for 70 minutes before returning to charge. It does depend on your lawn condition and the length of your grass. I found that once the mower is maintaining your lawn at the set cut height each day, my 4Ah battery in my smaller lawn area last for approximately 3 hours 40 mins and my 8Ah battery for my larger lawn area lasts for 7 hours 10 mins. The 8Ah battery option really is excellent and larger than the battery installed in most other robot mowers as far as I know.
Cut Quality
I am very happy with the cut quality so far. My lawns have never looked so well after 2 -3 weeks of operation. The 45MM cut height on my smaller lawn really has the appearance of a manicured lawn. The 55mm cut height of my larger lawn area also looks great and is described as a utility lawn height in the manual. The real benefit is the mulching feeds the lawn and you never have to worry about collecting and disposing of your grass clippings again. I have not changed or reversed the blades yet, but I did purchase some compatible blades.
Link to replacement blades:
https://www.amazon.co.uk/dp/B07F34V577?psc=1&ref=ppx_yo2ov_dt_b_product_details
Link to cable joiners:
https://www.amazon.co.uk/dp/B09C2X7H3B?psc=1&ref=ppx_yo2ov_dt_b_product_details
https://www.amazon.co.uk/dp/B07F8QXW19?psc=1&ref=ppx_yo2ov_dt_b_product_details
Mower Garage
I built a crude enclosure to put over the base station using 9x1 inch planks which was open at the end the mower drives in. This generally works well. However, I noticed that it can create problems when the mower tries to start mowing again after returning to the base station due to rain. The rain sensor is on the top of the mower at the back and is two nuts. When enough rain falls and pools between the nuts, it makes an electrical contact and registers the rain. The sensor is very sensitive and as the water starts to evaporate, the contact will be broken and the mower tries to reverse out of the base station. I noticed that when the mower moves, the water moves and makes the contact again which results in the mower driving forward back into the base station. This can happen multiple times and sometimes the mower tries to turn when this happens. The enclosure I built can interfere with that and the mower powers down as it gets stuck. When this happens you have to straighten it up, put in the pin and it will start again. Now my base station was not on completely level ground which wasn’t ideal. If you chose to build an enclosure, try and make it at least 5-10cm wider than the base station at it’s widest part and position the entrance in line with the base station and this issue may not happen for you.
Summary
I am really delighted with both of my Lidl robot mowers. Take your time with the planning, laying the ground wire and the correct positioning of the base station and you will have no problems. The mowers cost me 350 euros each which is a real bargain when you consider the equivalent Husqvarna model 310 Mark 2 retails for 1799 euros in Ireland. The Lidl mower also has a 3 year warranty which is excellent. I am only running them for about 3 weeks now and have experienced no problems so far other than having to slightly re-position the boundary wire on the slopes to prevent the mower slipping out of range. The condition of my lawn, time saving feature, price and 3 year warranty makes it an easy decision to purchase one. They might come up again in the specials in Ireland before the Summer is out as they have already come up twice before. If you want one, I suggest getting to your Local Lidl store early as they sold out quickly the last time.