Bosch Rotak 37 LI Ergoflex Review

Bosch Rotak 37 LI Ergoflex

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The Rotak Ergoflex, Bosch’s range of cordless rotary lawn mowers, are available in various sizes to suit different sized gardens, with the Rotak 37 LI Ergoflex falling into the mid-range category between the 32 LI and the 430 LI Ergoflex models.

This makes it suitable for most middle-sized lawns and the occasional large lawn, with the powerful electric motor and impressive battery making it one of the best performing cordless models on the market.

Let’s take a closer look at to see what it has to offer: 


  • 36V 4.0Ah Lithium-Ion Battery
  • 35 to 40 Minute runtime
  • 140 Minute Charge Time
  • 37cm Cutting Width
  • Six Cutting Heights (20mm-70mm)
  • 40L Grass Collector
  • Weighs 13.2kg
Bosch Rotak 37 LI Ergoflex Cordless Lawn mower
Bosch Rotak 37 LI Ergoflex Cordless 36 Volt Lithium-ion Rotary Lawnmower (37 cm Cutting Width)...
126 Reviews
Bosch Rotak 37 LI Ergoflex Cordless 36 Volt Lithium-ion Rotary Lawnmower (37 cm Cutting Width)...
  • 37cm/15in Cutting Width
  • 36 volt high powered Lithium-ion Battery, full recharge in 140 mins
  • 6 position adjustable height of cut from 20-70mm

Motor and Battery

The Rotak 37 LI Ergoflex features an electric motor powered by a single 36V 4.0Ah lithium-ion battery. Bosch have been at the forefront of the cordless mower market due to their impressive battery technology and the 37 LI Ergoflex continues this trend with one of the top batteries currently available.

When fully charged the battery has enough power to mow for around 35-40 minute depending on the lawn condition. This makes it perfect for most mid-sized lawns and some larger lawns too, with enough juice to cover areas of around 500smq, so it’s a versatile machine that makes mowing in bigger areas much easier and less restrictive.

One key feature for Bosch lithium-ion batteries is the use of Efficient Energy Management. This basically tells the lawn mower to adjust its power according to the condition of the grass, so the blade doesn’t overuse its power when it’s not needed, making this battery anywhere from 5-15% longer lasting than most others.

The battery does take around 140 minutes to fully charge, which is about standard for models in this size range. Should this be too long, the Rotak 37 LI also charged to 80% in around 70 minutes, which is great for those days where you only need to give the lawn a quick mow.

In terms of cutting performance, expect a smooth, clean cut on each pass, even having the power the remove tougher growth that some cordless models struggle with. This is thanks to the newly developed 37Li+ power drive that offers a high and consistent torque in all conditions.

Also, being battery powered means that the Rotak 37 LI Ergoflex produces no emissions and virtually no noise either.

Cutting Width

Bosch Rotak 37 LI Ergonomic handles

Being recommended for middle-size lawns and some larger lawns, it has a sizeable cutting blade measuring 37cm. This is a good size for mid-range areas because it brings the perfect balance of size and manoeuvrability – the blade is big enough that fewer passes are needed while its still compact enough to be easy to navigate around tight and narrow spaces.

Bosch cutting blades are renowned for their quality and durability. This is a strong, sturdy metal blade that doesn’t need much maintenance and will last for many years. The occasional sharpening may be needed down the line, although this should not be neccessary for some time and is easy enough to do.

Cutting Height

Like any good model, the Rotak 37 LI Ergoflex comes with a good selection of six cutting heights. This is a must for any mower, giving you the chance to adjust the cutting blade to accommodate the length of the lawn on any given day.

Ranging from 20-70mm, there are ample height selections to suit different lawn lengths whether it’s long, short, or somewhere in between. This makes maintaining a healthy and vibrant lawn much easier, as you can adjust the blade height to ensure you don’t remove too much grass any time you mow, helping to keep the lawn looking even and lowering the amount of weeds invading over time.

To adjust the blade height, simply move the lever found on the central cutting deck. It’s the ideal location for a height adjuster, being much easier to locate compared to front or rear levers.


Bosch Rotak 37 LI grass comb

So, how easy and comfortable is it to use the Rotak 37 LI Ergoflex?

It’s lightweight weighing just 13.2kg, is easy to operate and won’t tire you when using for longer periods. There are large wheels that make turning and navigating around grass quick and easy, even when moving around tighter spots such as corner areas or near a fence or garden shed.

It also boasts an ergonomic design, with dual handles offering plenty of grip and reducing the effect of vibrations, helping to keep fatigue and strains at bay. Known as the Ergoflex system, the design incorporates several power buttons throughout the handles but you only need to press one at any time, allowing people to find a comfortable grip when mowing. 

The dual handle design also makes it simple to manoeuvre. You can easily turn it in either direction thanks to the oversized grips, which is also handy when trying to mow through tougher grass.

Of course, being cordless certainly improves the usability of the Rotak 37 LI Ergoflex. There is no cord to worry about, so you can freely operate around the garden and not get tied up in anything or struggle to reach a part of the garden.

Extra Features

There are a few additional features included to help you get the perfect cut every time.

The first of these is a grass comb fitted at the side of the cutting deck. These gather up those longer stray blades of grass around the lawn edges that are easy to miss with the mower.

Rather than accepting defeat and forcing you to go back with trimmers or a strimmer, the grass combs gather up the loose grass around edges and remove them with ease and precision.

There is also a rear roller feature included that lets you get a striped effect on the lawn. Simply pull the mower backwards over the lawn to produce a stripped effect, alternating between each pass to produce a wonderful striped lawn.

Finally, there is a 40L grass box that will gather up all clippings in one go, saving the time and hassle of stopping to empty the grass box mid-mow.


  • Great battery life suitable for middle sized lawns
  • Lightweight and easy to operate
  • Nice selection of cutting heights for seasonal mowing
  • Includes grass comb and rear roller for creating the perfect lawn finish


  • Battery does take a while to fully charge but you can charge to 80% in about half the time


Bosch Rotak 37 LI Ergoflex Cordless 36 Volt Lithium-ion Rotary Lawnmower (37 cm Cutting Width)...
126 Reviews
Bosch Rotak 37 LI Ergoflex Cordless 36 Volt Lithium-ion Rotary Lawnmower (37 cm Cutting Width)...
  • 37cm/15in Cutting Width
  • 36 volt high powered Lithium-ion Battery, full recharge in 140 mins
  • 6 position adjustable height of cut from 20-70mm

Last update on 2024-05-17 / Affiliate links / Images from Amazon Product Advertising API

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