String trimmers are one of the first lawn care tools people buy when they’re ready to cut the cord or kick the gas can and make the switch to battery power. There are tons of options out there, so to help you narrow down the field as you’re shopping, I’m sharing what we look for when we’re evaluating a battery-powered string trimmer.
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Buying a Battery-Powered String Trimmer: Performance
Power
If your highest priority is performance, power is the best place to start. However, it can be hard to determine how much power a battery-powered string trimmer has. There are some clues to help us out, though.
First, check to see if it has a brushless motor. This motor design offers higher performance, longer runtime, and longer service life. A string trimmer with a brushed motor can be effective for light maintenance trimming, but I recommend a model with a brushless motor for most situations.
Then, take a look at the system voltage. Higher voltage isn’t always a guarantee of higher performance, but we can generally separate them into two groups of less. 18V and 20V Max systems have less power than the ones in the 40V+ category.
If the manufacturer mentions a gas engine equivalent, that’s the gold standard. Here are a few you might see and what they mean:
- 25cc equivalent: Entry-level Pro power that’s great for regular maintenance trimming and occasional overgrowth
- 30cc equivalent: Mid-range Pro power that can handle moderate overgrowth
- 35cc equivalent: High-end Pro power similar to a brush cutter that can handle heavy overgrowth
We can find more clues about the performance level when we look at cutting swath and line diameter below.
Pro Tip: Remember that string trimmer that uses zip ties instead of trimmer line? Avoid gimmicks like that.
RPMs and Modes
String trimmers can effectively perform light-duty cutting down to around 4600 RPM or so. Ideally, I like at least 5200 RPM for maintenance cuts and 5800+ RPM for high-productivity or overgrowth.
Most battery-powered string trimmers you can buy have at least two modes these days. Low helps conserve battery power for longer runtime and high offers the most productive cutting.
Some models have three modes. We see that primarily on the strongest models where mode one is good for light trimming, mode two handles regular trimming, and mode three tackles overgrowth.
Even if your model doesn’t have multiple modes, you can feather the trigger to use less power and extend your runtime.
Cutting Swath
All string trimmers have a rated cutting swath that tells you the maximum cutting diameter. For example, a 15-inch string trimmer creates a 15-inch circle with its line. The larger the cutting swath, the more area you clear at any given time. You also need a more powerful motor to have a larger cutting swath.
- 12 – 14 inches: Best for light residential maintenance trimming on small properties
- 15 – 16 inches: Best for moderate residential or commercial trimming on small to medium properties
- 17 – 18 inches: Best for heavy-duty residential or commercial trimming on large properties
Pro Tip: Many string trimmers have a cutter under the guard that you can flip around to use a smaller line length. For example, if you flip the cutter on a 16-inch trimmer, you’ll cut with a 14-inch swath. Using a shorter line length gives you more battery runtime since it requires less power.
Line Diameter
When you’re shopping for a battery-powered string trimmer, there are three main line sizes you’ll come across: 0.080-inch, 0.095-inch, and 0.105-inch. These measurements refer to the line diameter and larger line diameter require more power from the motor. Check to see what the maximum line size the trimmer is rated for to get an idea of its power level.
- 0.080-inch: Best for light-duty maintenance trimming
- 0.095-inch: Best for general-purpose trimming
- 0.105-inch: Best for heavy-duty trimming that includes overgrowth
Pro Tip: The line you use can make a big difference in cutting performance. While there are several quality lines available, we use Echo’s Black Diamond in our trimmers.
Runtime
While it’s obvious that the amount of runtime you need is based on how much trimming you have to do, most people overestimate how much they need. For example, you can cover a basic house on a 1/4-acre lot with about 10 minutes of actual trigger time, even though it’s longer from when you get your trimmer out to when you put it away.
One of the great things about a battery-powered string trimmer is that you can pop in a fresh battery and keep working if the one you’re using drains completely. Of course, you’ll need an extra battery on hand.
So, how much runtime do you need? It depends on how much trimming you have to do. For example, the same house on the same amount of land can vary greatly depending on whether there’s a fence and how many landscaping elements you have to trim around. Here’s what I recommend in general based on lot size:
- 1/4-acre or less: At least 15 minutes
- Up to a 1/2-acre: At least 20 minutes
- Up to 1 acre: At least 30 minutes
- 1+ acres: 30+ minutes
Pro Tip: You don’t need to hit these numbers with just one battery. Using multiple batteries to get the runtime you need is how most Pros get the job done.
Here are some tips to get more runtime if you’re running out of battery too quickly:
- Use a higher-capacity battery (this adds weight, though)
- Switch to a smaller line diameter
- Flip the line cutter to use a shorter line length
- Use a lower performance mode
- Feather the trigger instead of working at wide open throttle (WOT)
Vibration
Second to weight and balance, vibration can increase the amount of fatigue you experience when you’re trimming. Fortunately, most of today’s name-brand battery-powered string trimmers don’t have much of an issue with vibration. Nearly all of them have less vibration than a gas model.
There’s no good way to know how much vibration a string trimmer has by looking at the box or the manufacturer’s product page. Husqvarna is the only brand I know of that consistently reports vibration ratings. Reviews from quality publications should include notes on vibration, though, even if it’s on a subjective level.
Buying a Battery-Powered String Trimmer: Design and Features
Weight and Balance
Because it’s such a long tool, string trimmer weight has a big effect on fatigue and back pain. With some models weighing 15 pounds or more, they can be a literal pain. There are some ways to combat it, though.
The first is to go with a lightweight string trimmer. Anything 10 pounds or less (including the battery) qualifies. We consistently find trimmers in this weight class are noticeably easier to use and maneuver.
However, sometimes you need higher performance that only comes with a heavier working weight. If that’s the case, look for a model that includes a shoulder strap. At the very least, make sure it has a tether point for one and buy it separately.
Just because a trimmer is on the heavier side doesn’t mean it’s an automatic back-breaker, though. How the weight balances also comes into play. We prefer models that balance the weight as evenly as possible between the front and rear handles.
Even that’s relative, though. As you adjust the front handle’s position to get the most comfortable reach, you shift the balance slightly. The best bet is to give it a shot and see how it feels. If it’s straining your arms or back, add a shoulder strap.
Trimmer Heads
Probably the most likely thing to make someone curse their string trimmer is when it’s time to reload the line. Manual line loading sucks, and it’s even worse on dual-line heads. Since we only use dual-line heads, we demand rapid load designs.
Fortunately, most quality models come with a rapid load head these days. To load new line, you line up the loading indicators, run your length of line through to the halfway point, and then turn the cap to load it up. You don’t have to take the head apart at all.
Even if your trimmer comes with a manual load head, nearly every brand has a compatible rapid load model either from the manufacturer or a third party. Swapping heads only takes a couple of minutes and usually doesn’t require any special tools.
If you’re looking for the ultimate in line loading convenience, EGO’s PowerLoad head is even better. Instead of manually turning the cap, you just press a button and it does the work for you. EGO’s automatic features can be a little finicky, though. We recommend sticking with EGO’s own line to ensure the best performance.
Guards
The guard is one of the more minor considerations when you’re shopping, but it’s a pain point for some people. Most guards are either wide to block as much debris as possible or narrow to give you a better look at what you’re cutting.
Personally, I like a hybrid design like the ones Makita and Milwaukee use. It starts off narrow at the trimmer head to give you a good line of sight and then flares out wide to protect your legs.
Attachment Capability
Many people love multi-head attachment systems since you can get a whole suite of lawn care tools and manage just one powerhead. It’s an excellent way to save money and have all the tools you need to keep your lawn and landscaping looking great.
In most situations, I recommend avoiding the low-voltage systems and sticking with 40V+. For trimming and edging, 18V/20V Max can be effective, but with attachments like cultivators, blowers, or snow throwers, they can be underpowered.
Also, consider the connection style. Many systems have a “universal” fit, meaning you can use any brand’s attachments that have the same connection design. Milwaukee, Stihl, and EGO are a few that use their own connection type and don’t work with universal attachments.
Regardless of the brand you choose, make sure you’re able to get all the tools you want.
Buying a Battery-Powered String Trimmer: Value
Battery Systems
The battery that comes with your string trimmer is compatible with other tools on the same system, and it’s something you should consider. While you might be starting with a string trimmer, there’s a good chance you’ll want to add other tools down the road, like a mower, edger, leaf blower, or hedge trimmer.
18V or 20V Max systems tend to have lighter tools. Plus, brands like Ryobi, Skil, and DeWalt have tons of power tools that work on the same batteries. However, the lawn care equipment on those systems tends to have lower performance.
On the other hand, systems in the 40V+ range have higher performance and are more likely to feel like a true gas replacement. You’ll also get the best features and upgrades on those battery platforms.
In addition to the battery voltage and the performance it promises, make sure the system you’re buying into has the other tools you might want to add later.
Did You Know??? 18V is the same as 20V Max, and 36V is the same as 40V Max.
Price
Battery-powered string trimmers we recommend start around $100 (including a battery and charger) and can be more than $800, depending on how you want to kit it out.
For small lawns with regular light-duty trimming, you really can get started for about $100. For those of you who want something more high-performance, plan on spending $200 – $400, depending on the additional features and battery that come with it.
If you’re loading out a Pro trailer, plan to spend at least $300 on the trimmer, plus whatever batteries and chargers you’re going to use. The Pro game is very different, so you’re best off looking at what a full suite of handheld tools, batteries, and chargers will run as a full conversion to battery rather than piecemealing it together.
Warranty and Service
Most battery-powered string trimmers from brands we recommend have at least a 3-year warranty, though some might be shorter for high-hour commercial use.
Having a great warranty period is one thing, but how you get service for the warranty or repairs in general is a big deal. Here in central Florida, if I’m waiting six weeks to get my mower back, my lawn is going to look like a jungle.
Before you pull the trigger, take a look at the warranty pages for the brands you’re considering and see how their claim system works. While we expect the trimmers we buy to last well beyond the warranty period, it’s worth it to have a low-stress claims process in place if you need it.
For Pros, it’s all about the service centers in your area. Unsurprisingly, Stihl is the leader in the at category. They’re not the only game in town, so as you shop, talk to your dealer or rep and see what service after the sale looks like for the brands you’re considering.
