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Robot Autonomy, Classified
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ComparisonRobomow RK4000 and Greenworks Optimow 15

Up to three

All robot lawn mowers. Every figure below is placed against the whole class, so a gap can be read against how much the class itself varies.

Where each one suits you.

The conditions each robot was assessed against, side by side. Rows marked in gold are where these machines genuinely differ.

Fit verdicts by condition for each robot
Condition Robomow RK4000 Greenworks Optimow 15
Yard size
Under ¼ acre GoodRuntime stretches thin on a 1/4-acre lot in a single cycle; works fine with split sessions or a slightly larger model. GoodWell within the 0.37-acre coverage limit; capable, though a smaller-class mower may serve this lot equally well.
¼ – ½ acre Good3,000-7,000 sqft is the optimal range; single battery charge covers most yards in this band. GoodSits within the documented 1,500 m² (0.37-acre) ceiling; the Optimow 15 is rated for this size range.
Over ½ acrethey differ DependsYards over 7,000 sqft may require multiple charge cycles; runtime tops out at 2 hours per battery. PoorCoverage limit is 1,500 m² (0.37 acres); yards over half an acre exceed the documented operating limit.
Terrain
Mostly flat GoodRandom-pattern coverage completes reliably on flat ground; the pendulum-suspended deck needs no incline compensation here. GoodFlat terrain is fully within operating envelope; no gradient concerns apply.
Gentle slopes GoodRobomow rates the RK4000 to a 45% gradient (about 24 degrees); gentle slopes sit well inside that rating. GoodRated for up to 35% gradient; moderate slopes are comfortably within documented operating limits.
Steep / hilly DependsRated to 45% gradient (about 24 degrees) with passive slip-based traction; steeper banks exceed the rating and wet grass reduces grip. DependsGreenworks specs the Optimow 15 at 35% maximum; sections near that limit warrant extra caution when grass is wet.
Grass type
Typical lawn grass GoodRandom-pattern coverage completes over typical lawn grass with no reported cutting-quality issues on standard turf. GoodRandomized mulching-cut pattern designed for standard-height turfgrass on a regular mowing schedule.
Mixed / tall growth DependsNo published cutting-height range; mixed or tall growth performance is not documented for the offset-blade deck. DependsOvergrown grass above the blade design height may need a manual pre-cut before returning to regular automated sessions.
Thick (Bermuda / Zoysia) DependsBlade torque and cutting-height range for dense Bermuda or Zoysia are unpublished; performance on thick turf is unconfirmed. DependsDense thick-blade turf can slow progress; frequent short-duration passes are the documented mitigation for this grass type.
Boundary setup
Wireless required PoorThe RK4000 requires a buried boundary wire; there is no wire-free or RTK navigation mode available. PoorThe Optimow 15 requires physical perimeter wire; no wireless or GPS boundary option is available on this model.
Wire required GoodThis model is wire-guided by design; boundary wire installation is the standard, documented setup path. Good200 m of perimeter wire is included; the entire operating boundary is wire-defined, matching this setup.
No preference GoodAny boundary preference is satisfied here since the RK4000 ships as a wire-guided mower only. GoodThis model is wire-only; factor in the one-time perimeter installation before committing to this setup.

A robot being poor for a condition is a fact about fit, not a fault. “Depends” means the record names a limit worth reading, not that the answer is unknown.

Keep going.

The full recordRobomow RK4000Specifications, evidence, the Fit Check in full, and every tracked change.The full recordGreenworks Optimow 15Specifications, evidence, the Fit Check in full, and every tracked change.

Robovations classifies robots; it does not rank them. Nothing on this page is a recommendation, and no manufacturer influences a classification or its placement here.