Sun Joe iON100V-21LM-CT 21″ 100-Volt iONPRO Cordless Self-Propelled Lawn Mower Review

Sun Joe is a fast-growing outdoor appliance company. They include a line of well-engineered electric lawnmowers, including their iON100V-21LM-CT 100-Volt iONPRO Cordless Self-Propelled Lawn Mower.

It features a 20-inch cutting deck with a brushless motor that is powered by an onboard 2.5 Ah 100-Volt Lithium-Ion battery. This gives it enough charge to handle a mid-size lawn, with a runtime of up to 45-minutes. Though they do offer an upgrade to a 5 Ah battery which will power the mower for up to 90-minutes of normal use.

This self-propelled mower has an adjustable speed dial to let you comfortably dial it in to match your natural walking speed. It also has telescoping handles that you can adjust to the height of the user. They also help with compact storage when not in use. The cutting deck has seven different height settings ranging from 1.2-inches up to 3.75-inches.

It comes with a 13.2-gallon bagger system that collects grass clippings to leave you with a neatly trimmed lawn. Though if you prefer it can be switched over to side discharge.

Key Features

  • Self-Propelled Electric
  • 20-Inch Cutting Deck
  • 2.5 Ah 100 Volt Lithium-Ion Battery
  • Upgrade To 5 Ah Battery Available
  • Brushless Motor
  • 7 Height Adjustments For Cutting Deck
  • 13.2 Gallon Bagger
  • 2-Year Warranty Included In The Purchase
  • Telescoping Handles
  • Speed Dial Adjustment For A Comfortable Pace


Right out of the gate Sun Joe designed the iON100V-21LM-CT to run on a 2.5 Ah 100 Volt lithium-ion battery, which provides it with up to 45-minutes of runtime. This is usually sufficient for medium-to-small size lawns. If you have a larger lawn, you might want to consider the nicely priced upgrade to a 5 Ah lithium-ion battery, which will provide you with up to a 90-minute runtime.

Unfortunately, Sun Joe does not include a battery or charger in the initial purchase. You need to buy one separately. If you do, it’s best to choose a rapid charger with features like thermal, over-voltage, and over-current circuit protection. This essentially replicates what some other manufacturers call “Smart Charger.”

Ease of Use

Ease of use is one of the places where the Sun Joe iON100V-21LM-CT starts to shine. The self-propelled speed dial lets you closely match it to your natural walking speed. With some self-propelled mowers, you are forced to adjust to it which can either wear you down walking by walking too fast or frustrate your shoulders as you unconsciously start to wrestle it faster.

The telescoping handles are also easy to adjust. This lets you set them up to the comfortable height of the user, which can be a major feature for very tall or very short individuals. Especially those with large lawns.

Cut Quality & Options

The seven height adjustments let you customize the cutting height for the current conditions of your lawn. For example, if you have sandy soil and the recent weather has been consistently dry, you might want to set the mowing deck to its maximum height setting of 3.75 inches. This will slightly shade your turf for superior moisture retention.

Then let’s say that your area goes through a rainy period with a few sunny days mixed in. This will cause your lawn to grow like crazy. When it does you can simply dial the mower deck height down to it’s lowest of the 7 settings for a 1.2-inch high cut.

The Sun Joe iON100V-21LM-CT comes with a 13.2-gallon bagging system included in the purchase. This lets you collect grass clippings to prevent them from becoming dried thatch, which can suffocate the layers of your turf. It’s also a great way to feed your garden’s compost pile.

Though if you prefer, you can always set the mower up for side discharge. When cutting the lawn short, the small grass clippings can feed key nutrients like nitrogen back to your turf to support vigorous growth.


Since it’s an electric lawnmower, you don’t have to deal with things like messy oil changes and the recurring cost of oil and air filter replacements. Of course, like any lawnmower, you are eventually going to need to invest in replacement blades. Which is probably the better option with this mower, as opposed to trying to sharpen the arguably delicate blades yourself.

The battery is probably the thing that needs the most care. Lithium-ion batteries are more forgiving than Ni-CD, Ni-MH, and lead-acid batteries. Still, you don’t want to routinely overcharge them. So, when you do pony up for the battery, pair it with a charger that has features like thermal, over-voltage, and over-current circuit protection.

If you have room in the budget, you should consider buying the 5 Ah battery and accompanying charger. That way you know you have all the charge you need to tackle even a large lawn on a single charge.

Safety Features

The Sun Joe iON100V-21LM-CT has the usual hand-operated safety controls that you expect in a self-propelled walk-behind lawnmower.

Special Features

The sensitive adjustment of the speed dial lets you set it to a pace that closely matches your own walking speed. At the same time, the adjustable telescoping handle also lets you accommodate your height for maximum comfort while mowing. Along with the upgrade to the 5 Ah battery makes it very easy to mow a large yard.

Cost Effectiveness

There is a little bit of an argument to be made here on the topic of “Cost-Effectiveness.” On the one hand, electric lawnmowers are inherently more cost-effective than gasoline. Both in the cost to operate as well as to maintain. Fuel savings and not having to spend money year after year on oil changes, filters, carburetor repair, and inevitable spark plug failures help the Sun Joe iON100V-21LM-CT to pay for itself.

The two-year warranty is also a nice touch that insulates you against any early manufacturer defects.

The mark against it here is that it doesn’t specifically come with a battery and charger included in the purchase. Though, this is reflected in the friendly price tag. It also gives you the opportunity to select between the 2.5 Ah lithium-ion battery or the 5 Ah version.

8.5 Total Score
Powerful self-propelled walk-behind battery-powered lawnmower

  • Self-Propelled Electric
  • Variable Speed For A Comfortable Pace
  • 20-Inch Cutting Deck
  • 13.2 Gallon Bagger
  • 7 Cutting Height Adjustments
  • Brushless Motor
  • Battery Is An Additional Purchase
  • Charger Not Included
  • Self-Propelled Dial Isn’t On Handle
  • 2.5 Ah Version Is A Little Small
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Sun Joe iON100V-21LM-CT 21″ 100-Volt iONPRO Cordless Self-Propelled Lawn Mower Review
Sun Joe iON100V-21LM-CT 21″ 100-Volt iONPRO Cordless Self-Propelled Lawn Mower Review
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