Bosch UniversalRotak 2x18V-37-550 Cordless Lawnmower

In-Depth Look

Cordless mowers have reached the point where they genuinely compete with petrol for most domestic lawns. The Bosch UniversalRotak 2x18V-37-550 is the model that covers the majority of UK garden sizes with enough battery life and cutting performance to make a petrol mower unnecessary.

Dual Battery System

The dual 18V configuration uses two 4.0Ah batteries simultaneously, delivering 36V-equivalent power and runtime. Both batteries and the charger are included in the box, making this a complete out-of-the-box solution. On a fully charged pair, the mower covers up to 500m² before the batteries need recharging. The 4.0Ah batteries are compatible with other tools in the Bosch 18V UniversalSeries range, including the hedge trimmer and blower.

ProSilence Motor

At the rated noise level, the ProSilence motor produces less than half the acoustic pressure of a comparable petrol mower. This is a practical advantage in residential areas where early-morning or late-evening mowing can cause friction with neighbours. Many UK local authorities have restrictions on noise above certain decibel thresholds during specific hours; the ProSilence motor typically keeps the mower within acceptable limits where a petrol equivalent would not.

Cutting Height and Grass Box

Seven cutting height settings from 20mm to 70mm cover the full range from a closely cut ornamental lawn to a relaxed meadow-style height. The 40-litre grass box is adequate for a 500m² lawn before emptying. A full-indicator window shows when the box is approaching capacity. For very long or wet grass, the mower struggles more than a petrol equivalent — the standard recommendation of not cutting more than one-third of the grass blade height applies here as for any rotary mower.

Storage

The folding handles reduce the footprint for garage or shed storage. The mower should be stored with the batteries removed when not in use for extended periods, and should not be stored with wet grass inside the housing.

Verdict

The Bosch UniversalRotak cordless mower is the sensible, low-maintenance choice for UK homeowners with gardens up to 500m². No petrol, no cables, no excessive noise — and batteries and charger included from day one.

How It Compares

Against petrol mowers, the trade-off is straightforward: petrol still wins on raw runtime and cutting width for larger gardens, but the UniversalRotak wins comprehensively on noise, maintenance (no fuel, spark plugs, or annual servicing), and simply being ready to use without pull-starting. Against corded electric mowers, the obvious advantage is no trailing cable to work around or risk cutting through — a genuine safety and convenience improvement, at the cost of finite runtime between charges. Within Bosch’s own cordless mower range, the dual-battery 2x18V-37-550 sits above single-battery entry models in both cutting width and runtime, making it the better choice for anything beyond a small courtyard lawn; for larger gardens over 500m², stepping up to a wider-cut model or accepting a mid-mow recharge becomes more likely.

Common Questions

Will two 4.0Ah batteries really cover a 500m² lawn on one charge? Bosch’s stated coverage of up to 500m² is based on typical grass conditions; longer, thicker, or wet grass will reduce the area covered per charge since the motor works harder. For gardens near that upper limit, having a way to top up charge between sessions, or accepting the job might need a short pause to recharge, is worth planning for.

Can the batteries be used in other Bosch garden tools? Yes — the 18V batteries are shared across Bosch’s UniversalSeries garden tool range, including hedge trimmers and blowers, so a household running several Bosch cordless garden tools can share batteries between them rather than buying separate ones for each.

Is this mower suitable for a lawn with an uneven or sloped surface? Like most rotary mowers, it handles moderate unevenness and gentle slopes reasonably well, but it isn’t designed for steep gradients where mower stability and grip become a concern. For very uneven or steeply sloped lawns, checking the manufacturer’s guidance on safe operating angles is worthwhile before relying on it as the primary mower.