Sun Joe iON16LM 40V Cordless Lawn Mower
The Sun Joe iON16LM brings cordless freedom to your lawn care routine with a powerful 40-volt battery system that eliminates the hassle of gas, oil changes, and pull cords. This 16-inch walk-behind mower features a brushless motor that runs quieter than traditional gas mowers while delivering consistent cutting performance across small to medium lawns up to 1/4 acre.
We designed the iON16LM with homeowners in mind who want a cleaner, simpler mowing experience without sacrificing power. The 6-position height adjustment lets you customize your cut from 1.18 to 3.15 inches, while the rear bag collection system keeps clippings contained for a tidy finish. Weighing just 33 pounds, it maneuvers easily around flower beds and tight corners, and stores vertically to save precious garage space.
What makes the iON16LM stand out
Battery System & Runtime
The iON16LM operates on our 40-volt lithium-ion battery platform, which powers multiple tools across the Sun Joe cordless lineup. The included 4.0 Ah battery delivers approximately 40 minutes of runtime under typical mowing conditions, enough to cover lawns up to 10,000 square feet on a single charge.
The onboard charger plugs into any standard 120V outlet and fully recharges the battery in about 2 hours. Unlike older nickel-cadmium batteries, our lithium-ion cells hold their charge during storage and show no memory effect, so you can top off between mowing sessions without degrading capacity. The battery features built-in overcharge protection and a four-LED charge indicator so you always know how much power remains.
Cutting Performance & Deck Design
The 16-inch steel cutting deck strikes the ideal balance between maneuverability and coverage for suburban lawns. We engineered the deck with a tapered airflow channel that lifts grass blades upright before cutting, resulting in a cleaner, more even trim compared to flat-deck designs.
Height Adjustment
The single-lever height adjustment controls all four wheels simultaneously, offering six preset positions from just over an inch to more than three inches. Spring-loaded detents lock each setting firmly in place, preventing drift during operation. Most homeowners find the middle settings (around 2 to 2.5 inches) work best for cool-season grasses, while warm-season varieties like Bermuda thrive at the lower end of the range. The brushless motor maintains consistent blade speed even when cutting through thicker patches, eliminating the bogging common with brushed motors.
Collection & Mulching
The 10.6-gallon rear bag attaches via a simple lift-and-hook system that requires no tools and takes seconds to remove for emptying. Hard plastic reinforcements around the bag opening prevent collapse during use, maintaining consistent airflow for efficient clipping transfer.
The semi-transparent bag material lets you monitor fill levels at a glance, and the rigid frame design means you can empty the bag without grass clinging to fabric corners. When conditions allow, you can remove the bag entirely and let finely chopped clippings return nutrients to the soil, though we don’t include a dedicated mulching plug with this model.
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Common Questions About the iON16LM
The included 4.0 Ah battery provides approximately 40 minutes of runtime under typical conditions, which covers lawns up to 1/4 acre or roughly 10,000 square feet. Actual runtime varies based on grass height, thickness, and terrain.
If you have a larger property or prefer extended sessions without recharging, our optional 5.0 Ah battery extends runtime by about 25 percent. The battery recharges fully in approximately two hours using the included onboard charger.
The iON16LM handles gentle slopes without issue, but we recommend caution on inclines steeper than 15 degrees. The lightweight design makes it easy to push uphill, though the smaller wheels may lose traction on wet grass at steep angles.
Always mow across the face of a slope rather than straight up and down to maintain better control and footing. The battery is secured firmly in its compartment, so there's no risk of it shifting during angled operation.
Brushless motors like the one in the sun joe ion16lm use electronic controllers to manage power delivery, eliminating the physical carbon brushes that wear out in traditional motors. This design runs cooler, delivers more consistent torque, and requires virtually no maintenance beyond keeping the vents clear.
In practical terms, you'll notice the motor maintains blade speed even when cutting through thick patches, and the overall lifespan of the mower increases since there are fewer wear components to replace.
The cutting deck is constructed from stamped steel, not plastic. Steel provides better durability against rocks and debris while maintaining a rigid shape that ensures consistent cutting height across the entire width.
We apply a corrosion-resistant coating to the deck, but we still recommend hosing off grass clippings and mud after each use to prevent rust buildup in areas where the coating may chip over time.
The iON16LM comes configured for rear bagging, and you can remove the bag to discharge clippings directly onto the lawn for natural nutrient recycling. However, this model doesn't include a dedicated mulching plug that blocks the discharge chute and recirculates clippings for finer chopping.
For best results when mowing without the bag, keep the grass relatively short and mow when it's dry to prevent clumping.
Yes, we offer both 4.0 Ah and 5.0 Ah replacement batteries that work with the iON16LM and all other tools in our 40-volt cordless platform. Many customers keep a second battery on hand so they can swap mid-session without waiting for a recharge.
The batteries are interchangeable across the entire iON40V lineup, so if you already own our cordless string trimmer or blower, those batteries will work in the mower as well.
The blade attaches with a single hex bolt at the center of the deck. Before removing the blade, disconnect the battery and tip the mower on its side with the air vents facing up to prevent oil from entering the motor housing.
You can sharpen the blade with a standard bench grinder or file, maintaining the original bevel angle of about 30 degrees. If the blade is bent or excessively worn, replacement blades are available through our parts program. We recommend inspecting the blade every 10 hours of use and sharpening or replacing it at least once per season for optimal cut quality.