Kärcher LMO 18-33 18 Volt Cordless Lawn Mower Review

I was surprised at how small the box appeared when it arrived on my doorstep. I struggled to see how an entire garden mower could be this compact! On tearing into the box, it was clear that this is designed to be a super-compact and light weight piece of equipment.

I was impressed my how straightforward the assembly was too – it’s all pretty self-explanatory once you take a good look at the parts. You need to slot the lower section of the handle into the two holes until they click, then the top section of the handle is ready to attach.

Next up is screwing in the holding bolts. They have large handles on the inside of the frame that serve to hold everything rigid, but also allow you to fold down the handle when not in use. It’s a clever idea and is stronger than I first gave it credit for.

To attach the grass box, you flip up the rear hatch and insert it into the rear of the mower body. It took me a couple of goes to get it right at first, but that was me rather than the machine! The hatch is sprung so it holds the collection box nice and tight.

The final step is to insert the battery. It’s the same process as installing a battery into a combi drill: flip up the cover, slide the battery in until it clicks and you’re ready to tackle the lawn! Just make sure the red safety key is in place, or the mower won’t start up.

More famous for their quality pressure washers, German firm Kärcher make recognisable canary-yellow equipment. It’s not the most subtle colour, but I suppose it won’t ever get lost against the green grass in my garden…

I just can’t get over how light this thing is. To be honest, my first impression wasn’t great as I ordinarily associate heaviness with quality. But on inspection, the plastic casing is well shaped and rigid. It might look like a flimsy piece of plastic, but it has worked well for me since I started testing.

One of the clever things that Kärcher have done is made the body of the mower as wide as the wheelbase. It means that the blades cut almost as wide as the entire machine, so you can get up close to a wall or fence without it leaving too many tufts of untouched grass on the edge of your garden. That’s the theory, anyway.

The blades give you a reasonably wide 33 cm cutting path. It’s ideal for the smaller garden and means it can fit through narrow gaps between outdoor furniture or trees. If you had to mow a huge expanse of grass I’d probably pick something a little wider though.

But the real winner for people of all different heights is the adjustable handle. I’m over six feet tall, and it seems that most gardening equipment is designed for someone much smaller than me. I was really pleased to see that you can adjust the handle in two places, and at its maximum length it suited me just right.

You might ordinarily associate 18 Volt battery powered tools with small tools like drills or routers, but there’s more than enough juice in this thing to cut a reasonable size lawn.

The battery is a big chunky thing and is rated at 5.0 Ah. That’s not the most powerful battery I’ve ever seen, but it still gives you up to 24 minutes of constant mowing. For me and my diminutive lawn, that’s plenty of time. I suppose if you had a huge garden then 24 minutes might not be enough. But for most people it’s about the right amount of time to give an average garden a couple of passes at different lengths.

A really good thing about this battery system is that you can power share across the whole Kärcher 18V range. Whether it’s one of their lawn edging machines, weed removers, or leaf blowers, you only need to buy into the battery sets once.

The battery comes with an easy to understand LCD readout that gives you the remaining charge as a percentage. It’s more accurate compared with a more basic set of 3 LEDs you get on other battery systems. I like knowing how much power I’ve got left to finish off the garden!

Charging up is achieved with the help of the big charger that came with the battery pack. It’s designed like any other battery charging station and has wall mounting holes in the back so you can give it a more permanent home. According to Kärcher, it can charge from 0 – 100% in just over two hours. Not class leading, but it’s adequate.

It’s in this category that I had pretty low expectations. Lawn mowers spinning away at high RPM’s on Sunday afternoons are the cause of a high proportion of neighbourly quarrels, or so I assume. So, I expected this thing to sound a bit like a helicopter.

I was completely shocked and incredibly impressed by the lack of noise that the Karcher makes. The soft start winds the motor up in a second or two, but even at full speed it’s no louder than a hair dryer. And thanks to the electronic brake, as soon as you let go of the trigger, it stops!

Something I like about this Kärcher mower is that it’s simple. It doesn’t look like there’s much that can go wrong, which is a good thing in the long run.

For grass collection, there’s a semi-rigid 35 litre bag on the back. It folds down flat for storage and levers open to maximise internal space. I like the carry handle on top. It’s well balanced and forward enough to make sure the grass doesn’t spill out everywhere.

You can adjust the mowing height with a lever tucked away on the corner of the machine. There are three positions to choose from, but the action is hardly smooth. Moving the lever locks the height in with a pin through three different holes, but they’re black and hard to see. There’s a fair bit of plastic swarf around the holes too which isn’t great.

This mower comes with an interestingly shaped piece of black plastic that Kärcher call a “mulching plug”. Instead of the grass collection bag, you can insert this plug and turn the mower into a mulcher. As it runs across the lawn, it chops the grass up repeatedly into tiny pieces that fall back down as mulch. It’s a good way to improve your lawn health and means you don’t have to deal with so many bags of grass clippings.

Kärcher have obviously put a lot of thought into balancing this machine correctly. It’s quite long, but the position of the rear wheels and angle of the handle are optimum. It’s really easy to move around, thanks to the light weight and long adjustable handle.

One thing I liked about this mower is that it cuts almost to the full width of the machine, but in practise it wasn’t quite as effective. I was able to cut quite close to a wall, but because the handle assembly is also the same width as the machine, I was in danger of scratching up the paintwork on the handle. If the handle was slightly narrower it would cut much better up against walls.

I was initially sceptical about whether a single 5.0 Ah battery powered cordless mower would be up to the job. Compared with mains electric or petrol powered mowers it might lack a bit of up front grunt, but it’s more than capable when faced with an average lawn.

The mower is more than powerful enough once it’s spun up to full speed, but it can’t cope when you start it directly on top of long grass. The motor gets bogged down and stops when it feels it’s overloaded. This isn’t a major issue as I simply tilted the mower up, started up the blades, then dropped it back down when it was going at full tilt. An easy workaround indeed.

After testing this mower out for a few weeks and cutting my front and back gardens several times, I checked the blades for wear. I don’t know how long the blade is designed to last for, but I was disappointed to see several chips out of the blade edge already. I’d only hit a couple of stones, so this was bit disappointing.

The final proof of this mower was in the quality of the cut it made in my lawn though. Overall, I was quite impressed by how it cut the grass at the three different heights. It left a neat straight cut across the tops of the blades of grass and looked good.

I was a bit disappointed by the amount of grass cuttings that didn’t make it into the collection bag, but it’s a problem I’ve had with most mowers I’ve used in the past. The mower casing tends to get blocked up with grass during use, but I’m putting that down to mowing damp grass more than a defect with the mower.

My biggest safety concern with any corded mower is the cable itself. Wondering if it will snag on something at the worst possible time or making the classic mistake of mowing over the cord when it’s hidden in the long grass.

The absence of cord makes this mower so much safer simply because there’s one less thing to think about when you’re using it. You can concentrate on the task at hand without twenty metres of cable trailing behind you.

The next great safety feature I love about the Kärcher is the safety key. I’ve seen these devices on much more expensive machines before, but this small red piece of plastic is a potential life saver. If, like me, you’ve got small children running around, the last thing you want is for them to play with machinery like this.

The safety key is a simple piece of red plastic with a little loop for attaching to a keychain. Inside is a metal contact that completes an internal circuit when plugged in. Without this safety key the mower cannot run. When it’s not in use, you can store it away safe in the knowledge that anyone who you don’t want to use the mower can’t use the mower. Brilliant.

One of my favourite things about modern power tools and garden equipment is an electronic brake. It simply means that once you let go of the trigger it stops dead. There’s no wind down time or over-run where the only thing that stops the whirling blades is inertia. You’ve got a much better opportunity to save yourself in case something goes wrong.

This issue comes up again and again with cordless power tools of all sorts. You really need to pin your colours to the mast and pick a single brand of batteries and chargers. Unless, of course, you like spending lots of money on competing systems.

If you do a lot of garden work and you’re sick of dragging annoying and potentially dangerous power leads behind you, the Kärcher range of 18 Volt tools is impressive. The “bare” tools they sell that come without batteries or chargers offer good value for money as well.

This isn’t a particularly expensive cordless mower compared to some of the others on the list, but costs more compared with a basic corded mower. However, unless you have easy access to mains power in your garden, you’ll need to go down the cordless route.

The little yellow Kärcher LMO 18-33 Cordless Lawn Mower comes from the German experts behind everyone’s favourite pressure washer. They’ve combined sleek stylings with clever space-saving design to make this machine as compact as possible while still packing a 4,000 RPM punch.

Thanks to the onboard 18 Volt battery system there’s no need to drag round metres and metres of power cord, and there’s no danger of mowing over the cable ever again. You can’t cut acres of grass on a single charge, but it’s got more than enough juice to tackle a small to medium-sized garden.

Sure, there are competitors out there that offer more features and a larger grass collection box, but for the money I think this is one of the best cordless lawn mowers available right now. And it’s so quiet that my neighbours might not even know I’m cutting the lawn!