Hyundai HYM40LI420SP battery cordless mower review

Hyundai is a South Korean auto manufacturer known for their cars and motorcycles, so it may be a surprise for many that the company also produces lawn mowers. Hyundai mowers are typically petrol types, using the same engine technology found in Hyundai vehicles, giving them a reputation for exceptional cutting power and long-lasting durability.

Now the company has entered the cordless electric mower market with the HYM40LI420SP. This is a powerful mower suitable for larger gardens, equipped with an advanced Samsung lithium-ion battery that provides excellent runtimes and fast charging, while it comes with a host of features that most gardeners will find useful.

Let’s take a closer look at the HYM40LI420SP:


  • 40V 2.5Ah Battery
  • 42cm Cutting Width
  • 6 Cutting Heights (25m-75mm)
  • 45L Grass Catcher
  • Mulching Option
  • Self-Propelled

Battery and Motor

The HYM40LI420SP is one of the first electric powered mowers manufactured by Hyundai, powered by a robust Samsung 40V 2.5Ah lithium-ion battery. This offers about 30 minutes of runtime in ideal conditions, making it suitable for medium size lawns up to 350m2, which is slightly larger than the average UK lawn of around 250m2.

Charging times are similarly impressive, with an 80 minute charge time to get the better to 100%, which is quicker than many mowers with smaller batteries.

As with all cordless mowers, you can increase the runtime and make charging more convenient by purchasing a second battery, keeping a fully charged battery on standby so you don’t need to wait 80 minutes if your battery loses power before you finish mowing.

Another option is to purchase the Hyundai fast charger, which reduces the charge time to an incredible 30 minutes, offering even more convenience.

The HYM40LI420SP’s motor and battery offer almost unrivalled power, with the mower capable of dealing with thick and long growth, along with damper grass, with ease. Whether you are a hands-on gardener or prefer to take a low-maintenance approach, the mower has all the power you need. 

Hyundai are one of the few companies that also give you the number of charge cycles you can expect from the battery before it needs replaced. With over 1000 charge cycles in the battery, expect it to last for several years before needing a replacement, or even longer if you are switching between two batteries.

Simply put, this is one of the best li-ion batteries for a cordless lawn mower!

Cutting Width

Fitted with a 42cm steel cutting blade, the HYM40LI420SP has a great cutting width for tackling medium size lawns, mowing a lot of grass in a single pass. Many mowers for medium lawns feature a shorter cutting width so take longer to cut all the grass, highlighting how fast and efficient the HYM40LI420SP is in these size lawns.

The blade itself is premium quality, made from hardened steel and producing a clean cut across the grass. This is also removable so you can sharpen if needed, although we doubt that will be necessary for several years at least.

Mowing UK lawns means often dealing with damp and overgrown grass, so it’s good to have a lawn mower such as this with a reliable and durable cutting blade.

Cutting Height

The HYM40LI420SP comes with six cutting heights ranging from 25mm to 75mm, which is a good selection for seasonal mowing. You always want at least three cutting heights, preferably more, as this lets you leave the grass as long or short as the conditions require.

For example, during growing season we often mow more frequently when the grass is actively growing. This means keeping the grass shorter to encourage more growth, so you will want to use lower height settings in the 25-45mm height range.

Other times it is best to leave grass longer, such as those first few mows of the season when it still cooler outside and the grass takes longer to grow, which is where the higher settings become more useful.

Higher blade heights are also good for people that mow their lawn less often. You can leave the setting high and the mower will not remove too much grass at once – it is always recommended that you only remove one third of the length when mowing to encourage healthy regrowth.

So, the HYM40LI420SP covers all requirements with its blade height options, all of which are easily changed using the lever on the cutting deck.


Hyundai HYM40LI420SP grass box
Hyundai HYM40LI420SP handle


At 19.9kg the mower is on the heavier side, especially compared to other cordless mowers. However, this is still quite light and should not be an issue to move around as the mower also has a self-propulsion feature included.

This basically means that the mower does all the heavy pushing and pull for you, so using it is much easier than you might anticipate given the heavier weight and general robustness of the mower, which has a steel chassis.

The mower has a lot cutting power too, so the fact it is self-propelled is certainly a welcome feature that improves usability, allowing more people to take advantage of the mower’s power. Other features that help with usability include padded handles to reduce vibrations in the handles, and large wheels to make it easier to navigate uneven terrain.

Hyundai HYM40LI420SP features and spec

Grass Collector and Mulching

The mower comes with a sizable 45L grass collector, which is will have enough space for all your clippings without needing emptied before you are finished – even if working on longer grass that leaves more clippings.

Another great feature is the inclusion of a mulching function. This makes the mower gather and then further shred the clippings, dispersing them back onto the lawn. These fine clippings are essentially food for the lawn, breaking down and providing it with an added boost of nutrients, while also saving the hassle of needing to empty your clippings.


  • Excellent battery offers great runtime
  • Battery lasts over 1000 cycles
  • Amazing cutting power can handle less maintained lawns
  • Lots of cutting heights to choose from
  • Mulching function for improved lawn health


  • Is heavier than similar sized cordless mowers but self-propulsion means its not much of an issue beyond transporting from storage
Hyundai 16.5" / 42cm Cordless 40v Lithium-Ion Battery Self-Propelled Lawnmower with Battery and...100
  • No Cables, No Petrol, No Pollution - simply charge the batteries and you’re ready to go.

Last update on 2022-04-11 / Affiliate links / Images from Amazon Product Advertising API

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