Gardena Robotic Lawn Mower Review

We have owned the Gardena R40Li robotic lawn mower since I started this blog, back in 2013. In fact, one of the reasons I started the blog was to share my experiences and decision process, and as such now feels like the time is right to write a full Gardena robotic lawn mower review, having lived with the beast for three seasons.

For those who don't have time to read the full review, here are the bullet points. First, the good:

• The grass has never looked better;
• I got time back to do railway modelling instead;
• The whole experience has been almost pain-free.

Now, the not-so-good:

• Yes, it was expensive;
• Yes, parts fail (if you don't take care of it);
• Yes, moving the perimeter wire can be a pain.

The conclusion -- I would buy it again, but I'd take better care of it (i.e. clean it properly) and set it up a bit differently, probably getting in an expert to do that with me. After all, they did offer a free consultation!

Gardena Robotic Lawn Mower Installation

Installing the mower looked so easy on the DVD that came with it that I decided to go it alone, despite the kind offer to have someone come and help me install the perimeter wire (for free). One Sunday afternoon, instead of actually mowing with the old petrol-fired behemoth that it was to replace, I got stuck into the installation process.

The R40Li comes with it's own charging station, which sits on a perimeter wire, which stops the robot going off and mowing the tulips and neighbours drive when it should be doing the lawn. There's also a kind of follow-me cable that hooks up the mid-point of the perimeter wire to the charging station.

The idea is that, if the robot runs out of juice, it can find the wire, and subsequently find its way home. This is a system that works very well, but also has a dual use, as the wire can also be followed to a hard-to-reach part of the garden in case the mower is in danger of missing it due to a narrow entrance.

This is, in fact, something I regret not having done. 

Instead, my return loop is just a straight line. Having connected everything up and left it there for three years, I'm wary of upsetting the apple cart by relocating it, and probably the professional installer would have spotted my error straight away!

Other than that, once everything was in place, pinned down with the black plastic pegs and connected with waterproof 3M connectors (all supplied in the box), and plugged into my outside plug socket -- note, this is indispensible -- the mower charged up and was put to work.

It does take an afternoon of hammering little pegs in, testing electric circuits, and crossing fingers on occasion, but you can do it on your own. Just try to think it through a little bit more than I did!

Operation of the Gardena Robotic Lawn Mower

The mower runs on a daily programme, which can be varied through the slightly confusing on-board menu system. Be prepared to keep the instructions to hand for the first few weeks, as you'll be fine-tuning things like the time of day the mower should operate, and the number of times it follows the cable to the end before starting a run rather than just setting off in a random direction from the base.

And, the mower is governed by randomness.

It sets off when its charged, but pretty randomly, in a random direction, and changes that direction by a random amount whenever it hits an obstacle, or reaches the boundary perimeter wire.

Repairing the perimeter wire is also part of the ongoing operation and maintenance of these kinds of robotic mower, and it is a bit of hassle. Here's a tip: make sure you keep a long piece of single-core wire handy for troubleshooting, and don't bury the wire intentionally; just let the grass grow over it, or cover it with thin paving stones that are absolutely level with respect to the lawn.

The reason for this is that fault finding requires connecting one end of the cable to the base unit, and then hooking the other end to various points on the perimeter until you get a green light.

After the first few times, it gets a lot easier; but for that first time -- make sure you have wire handy, as well as a knife to scrape a little plastic off the perimeter wire, a crocodile clip to connect the wire to the perimeter cable, and some electrical tape to fix it up after...

Parts that Failed on the Lawn Mower

The first item in this category -- blades -- isn't really failure. You need to change the blades every so often.

Tell tail signs that the blades need replacing are:

• Wobbling mower caused by uneven weight distribution (one might be broken);
• Unusual noise;
• Grass tips going brown (unevenly cut; more torn than cleanly cropped).

Luckily, removing them is child's play; but don't let a child near them because they're sharp! They just unscrew from the underside, and the packs of replacement blades come with new screws and full instructions.

Then, the wheels came off. Actually, that's not true. What happened was the rubber came off, and the wheels stopped gripping (this was after 3 seasons use, with no over-wintering). The replacements have a solid, moulded tread, so they'll last for the rest of the product's lifetime.

Also this year, the dampers broke. The rubber perished, and they stopped preventing the outer bumper from bashing against the collision detection system, as discussed here.

Other than these few points, which encourage me to take much better care of the mower (i.e. cleaning it and overwintering it properly), the last three seasons have been trouble-free.

Summary - Should You Buy a Gardena R40Li Robotic Lawn Mower?

Here's the thing -- I can't answer that, because I have no idea whether your lawn qualifies. However, if you hate following your mechanical mower around a pretty standard lawn, then I'd certainly consider it.