How the test was made
All strimmers were used to cut grass and larger areas of weeds. The ultimate challenge was areas of tall nettles and young thickets of wild raspberry bushes. However, for the majority of the time they were tested on different types of tall and short grass. They have also been tested on wet grass.
We investigated the following parameters:
Performance – What height grass can the strimmer cope with? Does it strim as effectively throughout its battery life? How quickly can it cope with clearing different types of grass? How does the result vary when the grass is damp?
User-friendliness – How easy is it to assemble the strimmer? How easy is it to start? How can you adjust it? For example, is there a telescopic handle and can you set the strimmer head in different positions? Does it have any functions that mean you can go close to sensitive objects without damaging them?
Ergonomics – Can you strim throughout the entire battery life without getting pains anywhere in your body? How stable does it feel in your hands? Is it easy to use in inaccessible spots? What are the noise level and noise profile like?
Battery life and charging – How long does the strimmer run before you have to recharge it? How long does it take to charge the battery? Can you see how much battery life there is left? Can you see how much it has charged?
Functions and accessories – Has it any extra functions? What accessories are included?
The Ryobi RLT183225 is best in test because of its long battery life and effective strimming, making it extremely good value for money. Despite its long battery life, it's never too heavy for your back or painful on your hands. It also runs at maximum throughout the battery life and doesn't start to lose power towards the end. The rubberised handles give a good grip. The build quality feels solid, without any strange noises or instability in any parts when we wiggle or pull on them. It's easy to set the handle and strimmer head in the right position. However, it can sometimes be difficult to get the battery out of the attachment on the strimmer. We'd also have liked a plant protector to be able to get as close as possible to sensitive objects.
The RLT183225 is powerful and can cope with averagely difficult terrain. It deals with thick clumps of tall grass and weeds despite coming with a spool of line instead of plastic blades. However, it struggled a bit when it came to thickets of small wild raspberry bushes. For a strimmer, however, it does a more than acceptable job. The spool of line lasts for about seven medium-tough sessions with lots of grass and some weeds before you have to replace it. Replacing the spool is simple. However, something that's a little less pleasant is the strimmer's noise profile, which is quite strident. Another negative factor is that on a couple of occasions the line wasn't fed out enough so we had to pull it out by hand. But given the quality of the strimming, and above all how long it strims before the battery gives up, this is a really good purchase in the 18 volt class.
The Gardena Li-18/23R is a strong strimmer that's easy both to install and understand. It's supplied with plastic blades instead of a spool of line, together with a set of replacement blades. As standard, a blade is attached to the strimmer head. The blades handle everything we expose them to – from normal grass to tougher undergrowth and thick clumps of wet grass. But it wears out quickly. It gets significantly abraded even during the first strimming session. After this, the strimmer isn't really as efficient when strimming, as the more stubborn strands remain and you have to strim the same area several times. However, it can still cope with relatively coarse and more stable undergrowth. The blades then work for a further 3-4 sessions before they really need changing. They're very simple to change, with a simple click-in function. The installation of the strimmer is also very straightforward. All parts are snap on, so no tools are required. It's also easy to adjust the handle and the angle of the strimmer head. In other words, user-friendliness is high from start to finish. The strimmer is also relatively light.
The aspect we found to be negative about the design is that it's bulky and plasticky. The entire trimmer somehow gives a cheap impression. It could have been neater and had more rubberised details at the adjustment points. However, the battery life is good. The included battery gives you a cutting time of 25 minutes, which is very good. The battery is charged using a very small, neat charger. The battery also has an indicator that shows how much it has charged. However, we never really got this to work as it always seemed to show half full on our example even when the strimmer battery was completely flat. But the Gardena Li-18/23R is a powerful and very user-friendly strimmer with a very long cutting time. If it had received a little more love in terms of sustainability in the blades, it would have received top marks, but it's still a very good buy.
The AL-KO GTLi 18V Comfort is a strimmer with a spool of line that strims effectively and can cope with extremely tough terrain despite using wire instead of plastic blades. It can even cope with minor undergrowth such as young raspberry bushes and thicker weeds. However, it's not as efficient on wet, tougher grass. It has a useful automatic line feed feature. The line spool lasts for about five medium-tough sessions, mainly consisting of grass trimming, but also with some weeds, before it's time to replace it. It comes with an extra spool of line on the strimmer arm and you don't need tools to replace it. The build quality is generally quite high, although the line wears out quite quickly. The accessories included make this a serious machine, for example with an edging wheel and a metal plant protector instead of just a metal plant protector, and rubberised parts at points where you might hold the machine. The edging wheel makes it easy to go close to sensitive objects without damaging them, as the machine runs around them instead. Some of our testers found the GTLi 18V Comfort to be rather heavy. They also quite quickly developed sore hands and wrists, which we suspect is the result of slightly too much resistance in the handle. But we can't complain about the noise profile.
However, the cutting time isn't good, being slightly under average, and we'd have liked a few more minutes for it to get more points here. This is an extremely important aspect, so the score drops quite a bit. Another major disadvantage is that the battery doesn't have an indicator. However, the charger is small and neat so you can easily store it away when not in use, and the plug has an indicator light that shines green when the battery is fully charged. Overall this is a reasonable tool which would have had a much better score with a longer battery life.
The Stihl FSA 45 is a strong strimmer with double plastic blades in the head which clears both grass and tough weeds very effectively. You can easily replace the plastic blades by unclipping them from the strimmer head and clicking in new ones. It includes a couple of extra blades, which are tidily attached to the machine. You don't get many, but on the other hand they're very tough and you only need to change them every four or five sessions. You can also install a spool of line instead of plastic blades onto the same strimmer head. Assembly of the strimmer itself is very straightforward and only requires two screws. However, the battery is built-in and you can't disconnect it for charging – instead you have to plug in the entire strimmer. Nor can you change batteries with other products from the same manufacturer or swap between two batteries so that you can quickly get back to work. The FSA 45 is also special in another way, in that it includes a small plastic "key" that has to be inserted into the machine before it will start.
The FSA 45 is a neat strimmer in terms of size, and feels well-balanced and light when you hold it. Ergonomically, the user-friendliness is good. However, when it comes to actually cutting the grass, it's considerably less easy to use. This is largely because you have to slide a button forwards while at the same time holding in another button and handle to start the machine. But it also comes completely to a stop every time it runs into too much resistance. In other words, you can't simply lift the strimmer head to get it started again. This means that you have to do the starting hand movement over and over again during one session. This rapidly tires out both hand and wrist and can lead to cramp. Because it has a key that you can pull out as a safety function, we think that this is unnecessarily fussy. The battery life is good and it runs at full speed during the entire session. The machine is also very quiet.