Runtime is the number-one concern for anyone considering a switch from gas to battery-powered mowing. Gas mowers run as long as there's fuel in the tank. Battery mowers run as long as there's charge in the battery. So how long is that, exactly? And is it enough to finish your yard?
The answer depends on three things: your battery's voltage and capacity, your mower's efficiency, and the conditions you're mowing in. Let's break each one down.
Understanding Battery Capacity: Volts × Amp-Hours = Watt-Hours
Battery runtime is determined by the total energy stored in the battery, measured in watt-hours (Wh). You calculate it by multiplying voltage by amp-hours: an 80V 4.0Ah battery stores 320 Wh, while a 48V 4.0Ah battery stores 192 Wh.
More watt-hours means more runtime, all else being equal. But "all else" is rarely equal — motor efficiency, blade engagement, drive system, and cutting conditions all affect how quickly the battery drains.
Real-World Runtime by Greenworks Mower Model
The Greenworks 48V 14″ Push Mower with two 4.0Ah batteries provides roughly 35 to 45 minutes of continuous mowing. That's enough for most yards under 4,000 square feet — typically with battery to spare.
The Greenworks 48V 17″ Push Mower with the same battery configuration delivers similar runtime. The wider deck covers more ground per minute, so you often finish faster despite using slightly more power per pass due to the larger blade.
The Greenworks 80V 21″ Self-Propelled Mower with a 4.0Ah battery provides roughly 30 to 40 minutes of runtime. The self-propelled drive consumes additional power (since it's driving the wheels and the blade), but the 80V battery's higher energy capacity compensates. For yards up to about 8,000 square feet, a single battery is usually enough.
The Greenworks 60V CrossoverT Riding Mower uses six 8.0Ah batteries and can mow up to 2 acres on a single charge. This is a completely different category — the massive battery bank provides sustained runtime for large properties.
What Affects Runtime
Grass height and thickness. This is the biggest variable. Mowing a well-maintained lawn that gets cut weekly uses significantly less power than cutting through thick, overgrown grass. If you let your lawn go for two or three weeks, expect the battery to drain 30 to 50% faster on that first heavy mow.
Grass moisture. Wet grass is heavier and harder to cut. Morning dew or post-rain conditions increase power draw noticeably. For best runtime, mow when the grass is dry — late morning or afternoon on a dry day is ideal.
Cutting height. Lower cutting heights require the blade to do more work. Setting your mower to a higher cut reduces power consumption. This is one of the reasons lawn care experts recommend never cutting more than one-third of the grass blade height in a single mow — it's better for the lawn and better for your battery.
Terrain. Self-propelled mowers use more power on hills than on flat ground. If your yard has slopes, expect slightly shorter runtime compared to a flat property of the same size.
SmartCut technology. Several Greenworks mowers include SmartCut, which automatically adjusts motor power based on grass thickness. In thin sections, the motor throttles down and conserves battery. In thick sections, it ramps up. This intelligent power management extends runtime by 10 to 20% compared to mowers that run at constant full speed.
How to Maximize Your Runtime
Mow consistently. A weekly mowing schedule keeps grass at a manageable height and reduces the work the motor has to do each session. Skipping weeks costs you battery life when you finally mow.
Mow when dry. Wait for the grass to dry after rain or morning dew. Dry grass cuts easier and uses less power.
Start with a full charge. Lithium-ion batteries deliver the best performance from a full charge. Avoid starting a mow on a half-charged battery.
Keep blades sharp. A dull blade tears grass instead of cutting it cleanly. The motor works harder to push a dull blade through resistance, draining the battery faster. Sharpen blades at least once per season, ideally twice.
Clean the underside of the deck. Grass buildup under the deck creates drag on the blade. A clean deck spins more freely and uses less power. Scrape the underside after every few mows.
Own a second battery. For larger yards or when conditions are tough, a second battery eliminates any anxiety about running out of charge. Greenworks batteries are interchangeable within the same voltage platform, so your spare works in your blower and trimmer too.
Battery Lifespan: How Many Years Will It Last?
Runtime per charge is one question. Total battery lifespan is another. Greenworks lithium-ion batteries are rated for hundreds of charge cycles before capacity degrades meaningfully. For a typical homeowner mowing weekly from May through September — roughly 20 to 22 charges per year — a battery should deliver strong performance for 5 to 8 years of normal use.
Proper storage extends this lifespan significantly. Store batteries indoors at room temperature over the winter. Keep them at a partial charge (40 to 60%) for long-term storage rather than fully charged or fully depleted. Avoid leaving batteries on the charger indefinitely after reaching full charge.
The Bottom Line
Most Canadian homeowners will finish their mow on a single battery charge. If your yard is on the larger side, a second battery handles it. Runtime anxiety is the most common reason people hesitate on battery mowers — but in practice, it's rarely the limiting factor once you own one.