Robot Lawn Mowers buying guide

Robot lawn mowers are self-propelled lawn mowers that handle the grass cutting without you having to do anything. They are battery powered and use a charging station that they return to when the battery is running low. By following guide cables buried under the lawn and around trees the robot lawn mower knows what areas to adhere to.

The size of the lawn and steep slopes

Robot lawn mowers are optimised for different sized lawns. It’s best to choose a model that is adapted to a slightly larger area than your lawn is. Also, consider choosing a model that can handle slightly longer grass without any problems. Be aware that manufacturers are often a little optimistic in the specifications of what their models are capable of.

Robot lawn mowers can have problems with steep slopes or on uneven lawns. If you know that the lawn is sloping heavily, you should choose a more powerful model. If the lawn is uneven, larger wheels are needed. Tough, enclosed spaces and obstacles on the lawn can also be a set-back for a robot lawnmower. Read tests to see which models can handle obstacles the best.

If your lawn is bigger than a lawn mower can handle, you can use multiple robot lawn mowers who work together.

Navigation

Normally, you place a signal cable around the area where the robot lawn mower should work. When the robot mower arrives at the cable, it detects a radio signal and turns around. Built into the lawn mower is a computer that ensures that the entire lawn is cut, even though it might seem like the robot mower just runs smoothly back and forth over the lawn.

If you have a lawn that continues to the back, the robot lawn mower should support multi-zones. Otherwise, you must manually move it between the different grass areas. Bear in mind that sharp corners and uneven shapes are easier to handle for the more expensive mowers. A cheaper model will leave uncut areas that you must take care of manually.

Robot lawn mowers with accompanying guide cables find their way back to the charging station more easily.

Charging Station

The charging station is the site that the robot mower returns to every time it has finished cutting the lawn, where it charges the batteries, and takes protection from the rain (if there is a rain sensor on the mower). Place the charging station on the lawn and leave plenty of space both in front and to the sides. With protection from the weather over the station, the robot lawn mower will last even longer.

Battery life

A basic rule is that the robotic mower should cut longer than it charges. If the lawn mower needs to quickly return to the charging station, it may be due to several things. For example, the battery is getting old, the blades are dull or the lawn is wet. If you charge the lawn mower in strong sunlight, the battery will be warm and take longer to charge. Don’t forget to clear the underside of old grass that may be stuck.

Always charge the batteries in temperatures above zero and maintenance charge at least a couple of times during the winter months.

The blades

It’s important that the robot lawn mower always has sharp blades. How often you have to change the blades depends on the size of the lawn. A rule of thumb is that the blades should be replaced every 3 or 4 weeks or after 75 to 100 hours of mowing when the lawn is 1,000 square meters.

When you look at the sharpness of the blades you can scratch a little on a nail with the blade. Compare the sharpest outline with the part closest to the base of the blade. If the outer part of the blade edge slides on the nail instead of gripping it, it’s time to change or sharpen it.

There are blades for robot lawn mowers that are single-sided on one side and those that are reversible with a bevel on both. The thickness varies depending on the model, but usually is between 0.5 and 1.0 millimetres. When buying new blades, it should come with as many screws as blades in the package.

Make sure the blades match your robot mower before assembling them.

Theft

It’s best to choose a robot lawn mower with anti-theft protection. Personal PIN, built-in alarm and a GPS tracker make it less attractive to steal. If you forget your PIN, you must visit a service centre to get a new one. If your robot lawn mower has been stolen, you must report it to the dealer. It will then be blocked from service and maintenance at the workshop.

Safety

Robot lawn mowers have rotating blades that can damage both humans and animals. If you’ve got children or pets, models with a cutting disc with retractable blades are recommended. The blades should stop rotating if the robot mower is lifted from the lawn when in use.

Since robot lawn mowers do not take into account what's on the lawn, it's important to remove everything that should not be there. For example, hoses, toys and stones. Many small animals are most active at night, like hedgehogs. Therefore, always run the robot mower during daytime.

If the robot mower drives over a stone, for example, it’s important that the blades do not split and metal ends up in the lawn. Use only high quality blades that bend instead of break into pieces.