Best battery mower for thick, tall grass

Every brand in this category sells cutting power and none of them publishes a torque curve, so "best for thick grass" is usually written on vibes. This page does it the only defensible way: rank the published power specs, then show what a heavier cut does to the runtime numbers those same brands publish.

What each maker actually publishes about power

Read that table again and notice what it does not contain: a single figure that appears for more than one brand. EGO publishes torque, Greenworks publishes RPM, Kobalt and Toro publish neither. There is no honest way to rank these four machines on cutting force, and anyone who tells you otherwise is ranking them on something else.

So rank them on energy instead

Here is the part that is computable. Thick grass does not usually stop a brushless mower; it makes the motor draw more current, which drains the pack faster. So the machine that copes best with heavy growth is the one carrying the most energy for the load.

Notes on the picks

EGO LM2135SP: the only published torque figure, and three blades

Up to 7.0 ft-lbs of cutting torque is the only cutting-force number any of these brands puts in writing. Take it as EGO's own claim rather than an independently verified figure, but a company that publishes a torque number has at least decided to be measured on it.

The more practical advantage is the Select Cut system: three interchangeable lower blades — mulching, high-lift bagging and extended runtime. Heavy spring growth and a bagging blade go together; late-season dry grass and the runtime blade go together. It is the only mower here where the deck configuration is a decision you get to make after purchase.

#ad Check the EGO LM2135SP price on Amazon — how we're funded.

Greenworks LM2108S: 3200 RPM and a 4-in-1 deck

The published 3200 RPM blade speed matters in heavy growth because blade tip speed is what actually severs a thick stem. Greenworks is the only brand here that publishes it, and it publishes the same figure for its 40V push mower — which tells you the 80V machine's advantage is energy and drive, not blade speed.

The catch is the pack: 320Wh and a 33-minute claim. On the sensitivity arithmetic above, heavy growth takes that towards 22 minutes. Rated for half an acre, but plan on a second pack if your grass is thick.

#ad Check the Greenworks LM2108S price on Amazon — how we're funded.

Kobalt 80V: the most energy in reserve of anything here

640Wh installed across two 80V bays, a published 80-minute runtime claim and a one-acre rating. For thick grass over a big lawn, stored energy is the spec that decides whether you finish, and nothing else on this page carries this much. Kobalt does not state whether the two ports discharge together or in sequence, so we do not claim either — what is verifiable is that 640Wh is on the machine when you start.

#ad Check the Kobalt 80V mower price on Amazon — how we're funded.

Toro 21356: the steel deck argument

A 14-gauge steel deck is the only published material spec in this category. In heavy wet growth a deck accumulates clippings and takes knocks from hidden debris, and steel of a stated gauge is a more informative durability claim than any adjective. The 324Wh pack is the limit: 45 published minutes, less in heavy grass.

#ad Check the Toro 21356 price on Amazon — how we're funded.

The technique that beats any of these specs

University of Minnesota Extension guidance is to remove no more than one third of the leaf blade in a single cut. On grass that has run away from you, that means two or three lighter mows across a week rather than one heroic pass — which also happens to be the lowest-draw way to do it on a battery.

1. Raise the deck to its highest setting and take the top third off. On most of these mowers that is a 3.6 to 4 inch cut.
2. Wait two or three days. Drop one setting and cut again. Repeat until you are back at your maintenance height.
3. Use side discharge rather than mulching while the growth is heavy; recutting clippings is extra work for the motor.

More on where those heights come from, and why the deck's maximum setting is a spec worth checking before you buy, on the mowing height guide. If you are deciding what to do with the clippings afterwards, mulching versus bagging has the extension research on it.

What we cannot tell you

• Actual cutting force. One brand publishes torque, one publishes RPM, two publish neither. No cross-brand ranking of cutting power is possible from these documents.
• How much heavy grass really raises draw. Nobody publishes it. The 20/35/50% figures above are stated assumptions so you can see the sensitivity, not measurements.
• Whether a mower bogs down. That is a load-response behaviour that only shows up in use, and we have not used these.