The best cordless string trimmer is the EGO Power+ 16" with POWERLOAD and LINE IQ (ST1620T), and it wins on the part of trimming everybody hates: POWERLOAD reloads the spool by pushing a button instead of threading line by hand, and LINE IQ feeds line automatically as it wears instead of making you bump the head. If you want most of the capability for much less, the Greenworks 40V 16" is the value pick and comes with a 4.0 Ah battery.
Nearly every set of electric string trimmer reviews ranks on cutting width and runtime. Those matter, but they are not what makes a trimmer annoying to own. Line feed is. A trimmer that will not feed line, or that needs the spool rethreading in the middle of a job, is the one that stays in the shed. That is why the feed system sits at the top of our ranking criteria and why the machines that automate it win.
Battery trimmers have essentially displaced corded electric and small gas for homeowner use, and for good reasons: no cord to cut through, no fuel to go stale, no carburetor, and the weight is manageable. What you are really choosing is a battery platform, because the packs are most of the cost of your next blower, hedge cutter and mower. We have not trimmed with any of these; the ranking reads published cutting widths, feed systems, shaft types, voltages and amp-hours. See how we pick.
Best string trimmers battery powered: how to choose
Line feed first. There are three systems. Bump feedmeans tapping the head on the ground to release line — universal, cheap, and it works until it jams. Automatic feedreleases line as it wears, which is what EGO's LINE IQ does. And loading the spool is a separate misery: POWERLOAD winds the line for you from a straight length, where most trimmers need you to thread and wind it by hand. If you only pay for one feature in this category, pay for this one.
Cutting width, with a caveat. 16 inches is the full-size standard and 12 to 13 inches is the compact class. Wider covers more per sweep but also draws more current and needs more motor, so a wide head on a small battery platform is a false economy. Match the width to the platform.
Straight shaft or curved. Straight shafts reach further under shrubs, fences and benches, and suit taller users. Curved shafts are lighter, shorter to store and easier to control close in. Neither is better; they are different reaches.
Then the platform, which is the real decision.EGO's 56V range is the deepest in cordless lawn care and covers mowers, blowers and trimmers. Greenworks spans 24V to 80V with the widest value range. CRAFTSMAN V20 and Milwaukee M18 are tool-battery platforms first, which is exactly right if you already own the packs — the Milwaukee only makes sense if you do. WORX 20V PowerShare is the compact, light end.
Check what is in the box. Several trimmers are sold tool-only, and a battery plus charger can cost as much as the tool. The Greenworks and CRAFTSMAN picks here include a pack; others do not.
Trimmer or trimmer-edger. Some heads rotate 90 degrees to cut a vertical edge along a path, which saves owning two tools. It is a genuine convenience and it is not as good as a dedicated edger, which cuts a deeper, straighter line and holds it.
What cordless gives up to gas
Sustained power in heavy growth, and unlimited runtime. For a homeowner trimming around a lawn for twenty minutes, neither limit is reached. For clearing a long property line of heavy weeds, both are, and the honest answer there is a gas handheld or — better — a wheeled string trimmer, which cuts a 22-inch swath and carries its own weight.
The gas machines worth knowing about are in our main trimmer roundup, which ranks gas and battery together.
Getting more from a battery trimmer
Use the right line diameter for the head, and do not go thicker than specified — heavy line in a light head loads the motor and costs you runtime for no extra cutting. Keep the cutting plane tilted slightly so only the tip of the line contacts the grass; burying the whole line length in growth is what flattens a battery in ten minutes.
And trim before you mow, not after. The clippings then get mulched by the mower instead of lying in rows along the fence — which is also the argument for a mulching mower.
If battery is not enough for the job
Battery trimmers have closed most of the gap on grass and have not closed it on sustained heavy growth or on all-day runtime. Where those matter, the handheld gas machines are ranked in best gas string trimmer. And on any of these machines, running the diameter of line the head is rated for matters more than the brand of the trimmer: best string trimmer line.
A cordless trimmer will also tidy an edge if you turn it vertically, and the order you do that in changes the result - edge, trim, mow, then blow. How to edge a lawn has the sequence and the depths.
