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GreenWorks 20" Twin Force Cordless Mower: Pros and Cons From an Owner

I own a small construction company and employ four builders. I go though a lot of equipment, and I enjoy writing reviews. on them.


About the GreenWorks G-Max 20" Twin Force Cordless Mower

We live in Cincinnati and have an average section. I've owned the G-Max mower for over a year now when our gas-powered mower finally bit the dust. I've got to say I was pretty reluctant to buy a battery-powered mower as I've owned gas-powered mowers forever.

What changed my mind to a degree was my brother-in-law buying a G-Max a while back and swearing by it. Don't get confused with your ordinary electric motor-powered mower—these 25302 mowers are way different.

What makes this GreenWorks 20" really stand out is that it's powered by two electric motors operating two 10-inch blades. Powering them are dual 40V lithium batteries. This gives you about an hour runtime. But we bought an additional high-capacity battery, so we've now got a total of two hours runtime. Actually, I don't quite know why I did that, as my lawn takes only about 45 minutes to mow—must have got carried away by the purchase. Anyway, it doesn't hurt to have a spare. My experience with battery-powered drills is that the battery only lasts about two years anyway.

The great thing about the 25302 Twin Force lithium batteries is that there's no memory to worry about, and the charge time is only one hour.

The G-Max I've found goes through wet grass nicely and has an excellent single lever height lever giving a range of 1 -3/8 to 3 3/8 inch lawn height.

It only weighs 45 lbs too—about half of what my old gas mower weighed. That means I can hang it on the wall now instead of it taking up valuable floor space.

Problems I've Had With the G-Max 20" Twin Force

  • The company website doesn't have much information on it, and I still can't find an online manual for it.
  • In really thick grassy areas, the mower bogs down a little. It takes a little maneuvering to get through these areas—and you will go through a bit more battery juice doing it—but it will get the job done. In saying this, my gas mower struggled even more in very dense grassy areas, so in some ways this is actually a positive.
  • One of my batteries died after seven months, but GreenWorks did replace this under a week and under warranty.
  • Throttling: The G-Max 25302 Twin Force detects that it's in long grass, and so to compensate, it throttles up. It's a great feature, but the only problem I've found with this is that it takes a few feet of long grass before this feature kicks in—so in that time, it tends to die a little. It just means you've got to go back and mow that small strip of grass again. Maybe I'm getting a little picky here.
GreenWorks Twin Force Twin Blades.

GreenWorks Twin Force Twin Blades.

GreenWorks 20" Cordless G-Max Good Points

The obvious great point is lack of noise. With my gas mower, I was always conscious when mowing of the neighbors. Now with the Twin Force mower, I couldn't care less. The noise is minuscule. It's also very light to push in comparison as well.

Now with modern lithium battery technology, the dreaded memory is gone. In the past with a mower like this, unless the battery was completely run down, when charging, it they would never fully charge. This is no longer the case. Now you can fully charge it, run it down to say halfway, and fully charge it again.

You can run the mower with one battery installed—or what I do is run it with two. In this way, if you run out of juice on one battery, it automatically cuts over to the spare without stopping.

It's lightweight, turns easily, folds up in a snap, and takes seconds to switch between discharge/bagging/mulching.

The mulching is great. We've got some tall oak trees that drop copious amounts of sticks and acorns, and the G-Max makes light work of all this stuff.

In comparison to my old gas mower, I can now have a conversation with my wife without raising my voice. There's no smell and vibration of a gas mower. No longer after an hour will you have swollen hands from the vibration of a gas mower.


I'm thrilled with my GreenWorks G-Max. Apart from a couple of hiccups, throwing the old gas mower out the door is a real relief.

I bought it through Amazon because they offered free shipping, and it was much cheaper than the local stores in our area. Plus, it arrived in less than a week really well packaged and ready to go.

Questions and Answers

Is this self-propelled?

No, it's lightweight, so not necessary.

What is the warranty period for the G-Max?

The mower has a four-year warranty, and the batteries are covered for two years.

Does Amazon ship the 25302 with 2 x 4Ah batteries?


Does the Twin Force give a nice even cut, or do you have to mow the same area a couple of times?

It gives a very good cut and is great at mulching.

How well does the 25302 handle small twigs, say 1/8-inch diameter?

Not a problem.

What's the runtime on a fully charged battery?

Depends on how tall and thick your grass is. An average mow will give you 45–60 minutes battery life.

How long does the battery take to charge?

The small battery takes an hour and the large one two hours.

Does the mower come fully assembled?

Amazon sends it basically assembled. You've just got to assemble the handle and charge the battery, and off you go.

What size blades does the mower take?

Two 10-inch blades.

Is the G-Max handle adjustable?

It's not adjustable but is foldable for storage.

Do you have to remove the batteries of the 25302 to charge them?

Yes, you do.

Does the Twin Force come with a charger?

Yes, it does.

Can you mow without either the mulch attachment or the rear bag?

You can mow without the bag or mulch plug installed. It will just do a poor version of mulching, and you will have clumps of grass dropping out of the area where the mulch plug should be.

Is there an indicator on the unit indicating which battery is running and which is depleted?

No, there is not, but there are indicator lights on the batteries. Once one battery is depleted, it switches to the other one. With the included batteries, you're supposed to be able to get 70 minutes runtime. If you purchase another high-capacity 4Ah battery, up to two hours is possible

What is the actual tallest height-setting on this mower?

The height setting for this unit is 1 3/4" to 3 3/4".

Can you buy a second 4Ah battery for the GreenWorks 25302 G-Max 40V Twin Force 20-inch cordless lawn mower and use two 4Ah batteries in it?

Yes, you can purchase a separate G-Max 40V 4Ah battery and insert two 4Ah batteries at the same time in the mower. The mower only runs one battery at a time.

Is this mower's batteries good to use on other products, such as the trimmer, blower, and edger?

Yes, as long as they are all G-MAX. I only bought the batteries with the lawnmower, and I bought the blower, hedge trimmer, and weed-eater with no battery—using the ones from the lawnmower

Does this mower have metal blades?

The G-Max has steel blades.

Only $316 delivered to your door

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: I just bought this Greenworks Twin Force mower, and the first thing I did was charge up the batteries as suggested. Once they were fully charged, I installed them in the machine. When I fired it up everything seemed ok, but a red light came on for one of the batteries. Is a red light a problem on the Greenworks Twin force mower's battery?

Answer: Good on you for buying one! Such a great mower. No, the red light is not a problem. It's telling you that the big battery is in use. When that runs out, it'll switch to the smaller battery and the red light will come on for that one. When they switch over you may get a feeling like a car changing gears.

Question: After a short amount of run time, my Greenworks mower shuts off and a red blinking light comes on the batteries. What could be the reason?

Answer: Check the cable that runs from the handle to the engine. These can get lose. If there's any slack, try to tighten it. You might also have a short somewhere that's quickly draining the batteries. Greenworks has a toll-free helpline: 1-888-909-6757, or 1-888-90WORKS.

Question: Is the Greenworks G-Max Mower equipped with a "brushless" motor?

Answer: Yes it's a brushless motor

Question: Does this charging system have smart charge technology?

Answer: Yes, you can. The charging system has an electronic sensor that will stop charging the battery when it is fully charged.