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GreenWorks G-MAX 40V 4.0Ah Li-Ion Battery

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Product overview

Product overview

The GreenWorks G-MAX 40V lithium-ion battery system delivers longer run time, higher performance, and greater output among all GreenWorks G-MAX tools.

About GreenWorks The future is here and it's electric. Once you’ve experienced the power, convenience and economy of a 40V garden tool there will be no going back. The G-MAX 40V Li-Ion range from GreenWorks is already a best-seller in the US and Europe, now it’s ready to revolutionise the way Kiwi’s take care of their backyard.

GreenWorks tools are clean, green, quiet and maintenance free, with no compromises – experience the future today.

• 4.0Ah, 40V Lithium-Ion battery
• Compatible with all products within the GreenWorks 40V range
• Fast charging
• No memory effect
• No self-discharge
• One GreenWorks G-MAX 40V battery powers all Greenworks 40V tools
• 3 Year Greenworks Battery Warranty

Product code: 2927007
Model: G40B4
Voltage: 40V
Charging time 100% (4Ah): 120mins
Battery pack capacity: 4Ah
Watt hours: 144Wh
Weight: 2kg

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Customer questions

Questions and answers

0 votes
q: How much time does the battery last for before it runs out while in use?
a: This is not an easily answered question, this is rated at 4Ah (amp hours), which means it has enough charge to run for an hour when a steady current of 4A is being drawn. However in practice no tool really runs like this - it depends on power needed to run the tool and loading required by the job. So even on the same tool (say a chainsaw) the run time will change depending on the hardness of the wood etc.
By Trade Tested on January 5, 2021
2 votes
q: How many discharge cycles is it rated for?
a: Up to approx 2000.
By Trade Tested on January 20, 2020
1 vote
q: Is it a direct replacement for the 2 AH unit and does the charger suit both 2 and 4 AH Batteries?
a: Yes to both.
By Trade Tested on March 26, 2020
0 votes
q: Hi will this be suitable to replace the Ryobi 36v battery and if so will the ryobi charger work with it?
a: No it won't, these are not cross-compatible with other brands (and vice versa).
By Trade Tested on May 20, 2020
Customer reviews

Customer reviews

Overall rating

4.8 out of 5 stars from 52 reviews
Kane's GardeNZ Christchurch

GreenWorks G-MAX 40V 4.0Ah Li-Ion Battery

about 1 month ago


Brought this as I have the 2Ah and the 6Ah battery. By far my favourite battery as the release button is easy to grab out of the pole saw, hedge Trimmer or leaf blower . 6Ah battery and 2Ah battery stick quite a lot and need a really good grip to get them out. But 4Ah battery button design make it way easier

Chris Waikato

Great battery

about 1 month ago


Lasts a long time. Get the whole lawn mowed on one charge. I can load it in to the blower vac and clean the driveway.

Ralph Auckland

Not much to say really

about 1 month ago


Exactly what you would expect. Extra batteries mean you can do the job without waiting for them to recharge. The upfront cost of batteries is the biggest downside to battery power but it is what it is.

RogerD Waikato

GreenWorks Lawnmower Battery

2 months ago


Got as an extra to use when the lawns are out of control and more power is needed to finish the job. Works a treat.

Old thomo Masterton


3 months ago


Awesome I can mow 800 square meters, on one battery charge

Hans Auckland

second mower battery

3 months ago


Purchased this as the mower came with only one battery and if in the middle of doing the lawns it's annoying to wait for a recharge so purchased a second battery and now I can finish all the lawns in one go, holds charge well and has a handy charge level indicator. Very happy with this product

Nita Southland


3 months ago


Excellent battery for having as a spare.

Chris Auckland

Extra battery

4 months ago


Good to have with a larger lawn.

ShaunH Patea, Taranaki

If you need extral power

4 months ago


I got this so I wouldn't run short when mowing the 1/4 acre. All good, it's good having a spare as then I can get straight into the weed whacking when finished the mowing.

Tweet Wanganui

Green Works battery

4 months ago


Great battery compact and easy too use.

Rk Auckland


4 months ago


Very powerful battery. Easy to charge.

Matthew Hillcrest

Perfect for my needs

4 months ago


Easy to use, and fast to recharge. Powers my mower perfectly on my small to medium section.

Ned Manawatu

New Battery

4 months ago


With only one battery and a very large lawn, one battery was not quite enough if the grass got a bit long. A 2nd battery and problem solved. Lawn mowed in one go !

Battery Powered Invercargill

Back up Battery Saves the Day

5 months ago


One battery is enough to get the yard done if you keep the grass short. We had long lawn on our hands when we first started, though, and we found out very quickly that we'd need a back up battery if we wanted to wrangle that and whack weeds on the same day.

Mike Waikato


5 months ago


Very happy with this product

David Canterbury

Gives endurance to tools

5 months ago


Gives 30 minutes + usage to line trimmer and hedge trimmer tools.

Happy Mower Auckland

Great spare

7 months ago


Great to have a spare as it doesn’t last more than about 30/40mins when mowing the lawns and I need a good hour for that.

Nathan Hastings

Fine addition!

10 months ago


I purchased another battery to go with all my existing Greenworks equipment, so I had 2. Makes life easier if I forget to charge one. It works great! No problems!

Deano Katikati, Bay of Plenty

G-MAX 40v battery.

10 months ago


I brought this battery as a backup for my lawnmower. The 1st battery ran for 40min. in which it mowed nearly the whole section (525sq metre) which was partly wet and dense in places. I then plugged in the 2nd battery to finish off, which took 10min.The battery only used 1 bar.

Jas Auckland


about 1 year ago


Plenty of battery life to complete jobs without worrying about a flat battery part way through.

Kiwi ally Auckland

Great Battery

about 1 year ago


Holds its charge well and gives 40 minutes of continuous mowing. I have two of these batteries for my Greenworks lawnmower, which has been the best investment I've ever made.

Ewie Otago

Greenworks Battery

about 1 year ago


I bought this as a back up battery for my Mower. Works well, lasts longer than the Victa battery, and is quite a bit cheaper. You just have to cut a couple of tags off so it fits in my Mower's connector.

Rose de Haan Otorohanga

great power from this battery

about 1 year ago


I have purchased a second battery fro my GreenWorks lawnmower as my lawn is large and i was not able to get it all done on one battery but Im impressed with the length of time and power i get out of this 4Ah battery.

Browny Hawera

4.0AH battery

about 1 year ago


The 4.0AH battery has a longer endurance than I expected. Plenty of power and time.

Pk whanganui


about 1 year ago


I needed this extra battery for my Greenworks lawnmower. it lasts up to 40 minutes depending on how thick the grass is. It's great to have a spare battery as a back up.

Jamie Nelson

A bit more time

about 1 year ago


Brilliant add on to the mower having two batteries now as we live on a large 3000m2 section. Even have left the ride on in the shed a few times now

Bob Otago


about 1 year ago


Wow! So happy with this battery so I brought another 2. I have several GreenWorks products that I use and these batteries last and have heaps of power - Awesome!!!

Jim Greytown

GreenWorks G-MAX 40V 4.0Ah Li-Ion Battery

about 1 year ago


It's a battery.

Brian Upper Hutt

Greenworks Pole Chainsaw

about 1 year ago


Delighted with the pole saw it is easy to manage not to heavy.

Mark Wellington

Excellent Power and Charge

about 1 year ago


Great combination products – do all they’re expected to, and certainly deliver extended output and solid power. Recharge is a breeze. And as someone else has mentioned; while the battery is heavy, this ensures it provides a good balance to the tools.

Charlie Auckland

GreenWorks G-MAX 40V 4.0Ah Li-Ion Battery

about 1 year ago


Works as described. Heavy wee sucker.

Gra Manawatu

Bat & Charger

about 1 year ago


No issues all is functioning well .

Adele Taranaki

My review

over 2 years ago


Excellent and easy to use and manage. I love owning this

Paulo Auckland

Heavy duty battery

over 2 years ago


Great product, got the bigger battery so I can change tools to complete the gardening without having to recharge. Its working great.

Sir Mel Bay of Plenty

Batteries and replacement line trimmer wire

over 2 years ago


I cannot say enough for Greenworks products they have never failed and last the time to do the work expected of them

Giuli Nelson


over 2 years ago


Great product. Lasting well and still goes for half hour forty min on lawn mower and longer on hedge trimmer. Very happy to have two

Bill Stratford

40volt battery

over 2 years ago


Works fine

Dave Southland


over 2 years ago


Great staying power. Seems to go forever between charges

TTirapelle Wellington

Best for now....

over 2 years ago


Hope we could have the 5AH Battery. but now that I have 2 of this 4, I can finish the job in one go.

Bill Wellington

Lots of power

over 2 years ago


Great battery powers my mower and blower on one charge and recharges quickly. Excellent value.

Mickey Wellington

Li Ion battery

over 2 years ago


Arrived promptly, works fine

Kenson Auckland


over 2 years ago


Works as advertised no issues so far. Plenty of capacity for my use, ie, a home garden

Shaun Auckland

G-MAX 40V battery

over 2 years ago


The battery delivers plenty of power to the chainsaw. I held off buying a second battery until I tested the first. i will buy a second one now

Chrissy Southland

Great power

over 2 years ago


Truly happy with the power I received and this 4.0ah size just lasts a long time.

Gavin Warworth


over 2 years ago


What a brilliant product and keeps its charge lobger than I would have thought. Have purchased the GreenWorks Chainsaw, Pole saw, Trimmer and Blower previously and they are fantastic. Going to the battery tools is certainly easier and easier especially for the smaller jobs although I have used all of them quite hard too.

Morri Manawatu

Essential battery for greenworks tools

over 2 years ago


Good design, has handy status gauge for seeing how full it is. Good to have a spare so you're not waiting for first one to charge.

Mikep Christchurch

Greenworks battery

over 2 years ago


Big 4 amp hour battery enables my chainsaw and line trimmer to work for longer than I have the strength to use them! Recommended.

Sledge Auckland

Great product

over 2 years ago


Brilliant product will be buying blowers and mower in the future.Reg Danny Auckland.

DB Tararua

GreenWorks Gmax40v battery

over 2 years ago


Got a spare one to go with lawn mower just in case I’m too slow with mowing using the first one

Sidewinder Hawke%27s Bay

Battery 40 volt

over 2 years ago


Good battery life.. goes all day in the chainsaw.. 4 amp Happy with it.. be good if other tools available like angle grinder, die grinder etc that takes the 40 volt batteries

Stumpgrinder Hawke%27s Bay

Greenworks 40 volt Batterys

over 2 years ago


Like the 4 lights that show how much life is in battery, seem to be reasonable running time, need to have a spare battery charged up for a spare.. I have two batterys

Caz Bay of Plenty

Battery power

over 3 years ago


Big battery and lasts forever

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