We reviewed this mower when it was initially released. At the time 40V lithium-ion batteries were some of the more powerful on the market. Since then the Pro 20 has fallen behind. It's priced similarly to several 80V and higher models including another Greenworks model, and the Snapper XD (82V) These two are currently ranked at the to of our best battery-powered lawn mowers.
Our Greenworks G-Max Pro 20 Review
The total runtime with the stock batteries comes in around 70 minutes, which should be more than sufficient for the average user. With its adjustable height, rear-discharge bag, and mulching capabilities, the Twin Force is one of the most feature-packed cordless electric mowers currently on the market.
The Twin Force isn’t just powerful and easy to use, it’s also eco-friendly, unlike those gas guzzlers that deplete our ozone layer.
The Twin Force is a walk-behind electric mower that relies on its 40V lithium-ion battery for power. It is cordless (no bulky wires or extension cords to mess with) and can run for 50-70 minutes after you have fully charged it’s two batteries (included with purchase).
The mower has 5 height settings, a 20-inch cutting deck, and two smaller blades rather than one large one.
It has full mulching, bagging, and side-discharge capabilities. The mower itself comes with a 4-year warranty and the batteries offer a 2-year warranty. The Twin Force weighs in at a VERY reasonable weight of 42.5 lbs.
The Twin Force operates on Greenwork's G-Max battery system. They are compatible across a wide range of devices including trimmers, mowers, and leaf blowers. They charge quickly and will generally last between 60-70 minutes while mowing.
Because the PRO-20" uses a brushless motor, Greenworks has built in an intelligent speed monitor that increases the power output whenever your mower passes over denser areas of your lawn. This is a common feature among electric mowers.
They have also incorporated a dual-blade cutting system. Electric motors don't generate the same amount of torque as gas-powered many manufacturers opt for smaller dual-blade systems. Smaller blades require less power.
This solution sounds like a good idea, but in practice you often end up with patches of grass that get missed. This becomes more pronounced in thicker or taller grass. The mower has no way of preemptively boosting power so you've generally moved a couple feet before it engages more power. This leaves areas of grass that will need to be re-cut.
Ease of use
In general, most electric mowers are relatively easy to use. Startup couldn't be any simpler; place the battery in it's slot, ensure the safety cord is attached, engage the bail bar, and press the start button. No you're ready to mow. Maintenance is a snap as there's no oil changes or draining fuel at the end of the mowing season.
The handle comes separately but it doesn’t take very long to assemble it — 5-10 minutes would be a conservative estimate. What you’ll notice during the assembly process is that the handles can fold over each other for easy storage.
There are 10" wheels in the back and 7" in the front. This combined with the light weight on the unit makes maneuvering it a breeze.
As we mentioned above the dual-blade system is designed to compensate for the lower power of electric mowers. This system performed really well in thinner grasses that weren't too tall. But once you move into thicker or taller grass you'll notice some missed spots that require an extra pass.
It's important to keep in mind that this mower isn't designed to work on thick grasses. If you've got bermuda or another thicker variety you'll want to look at more powerful mowers. If you live in the Southeast or where theres generally more humid conditions you might even consider an electric mower with a cord.
The mower has a total of six positions that range from 1.15 inches to 3.5 inches.
If your lawn has grown too high, just start mowing your lawn on the highest setting and then reduce your height to the desired level for your second pass. With the Twin Force, it’s quite easy to select your desired height, a single pull on the lever will adjust all four wheels at once.
It isn’t often that you see a cordless mower with this much power. In fact, it only comes around once in a blue moon. If we were rating mowers based on their power alone, the Twin Force would be the best electric mower, period.
Its two stock batteries — one being 2Ah and the other 4Ah — provide a constant supply of power to fuel the dual blade’s motor. The best part is that the motor automatically increases its speed whenever it deems it necessary.
The two batteries have an average combined runtime of 60 minutes. It only takes 3 hours to fully charge both batteries making it easy to mow your lawn on a daily basis if you wanted to.
One major downside of the Twin Force is its cheap rubber grips on the handles. It makes no sense to me why quality companies spend years designing optimized grass-slicing machines and then proceed to cheap out on the components that cost the least.
Like the handle grip, the bottom rear rubber guard is quite subpar and tends to deform at times. The deformation wouldn’t be that big of an issue if it didn’t occasionally go underneath the mower, but unfortunately, that's exactly what it does.
Is It a Good Solution?
The PRO-20 is a decent mower, but the fact that it's priced so close to other mowers (including other Greenworks cordless mowers) in the 80V category makes it somewhat obsolete. The dual-blade system combined with the engine continuously adjusting speed and power based on cutting conditions was more a source of frustration than help. Anything other than thin, dry grass often requires a second pass.
More Lawn Mower Reviews
We much prefer the Greeenworks 80V model if you're partial to the name, otherwise our top pick overall is the Snapper XD 80V.
Read about zero turn lawn mowers here.