A dying battery in the middle of mowing can instantly transform yard work into a frustrating chore, particularly when dealing with larger or overgrown lawns.
For owners of Greenworks 40V mowers, reliable performance is paramount, as inconsistent power and short runtimes undermine the convenience of cordless yard care.
Reliable performance hinges on choosing the right replacement or spare battery that efficiently meets your mower’s demands.
To ensure strong, uninterrupted power, you should look for a Greenworks 40V battery with high amp-hour (Ah) capacity and robust build quality.
These top batteries seamlessly support the entire 40V lineup, from mowers to string trimmers, making them ideal for integrated yard care.
We prioritized real-world performance, user feedback, and warranty coverage across the leading models to find the best options for 2025. Find your ideal battery match below and keep your lawn looking sharp all season long.
1. Greenworks 40V 4.0Ah Genuine Battery (Best Overall)
The genuine Greenworks 40V 4.0Ah battery delivers rock-solid reliability and seamless integration across the brand’s expansive ecosystem of 75+ tools.
As the most trusted OEM option, it is positioned as the ideal pick for owners prioritizing reliability, warranty support, and seamless tool communication over maximum runtime.
It delivers 50% more capacity than the base 2.0Ah model, significantly extending runtime, which is perfect for users tackling medium to large yards without constant recharging.
The built-in 4-LED fuel gauge offers precise charge visibility, eliminating guesswork, and the 1-hour rapid charge capability ensures minimal downtime between mowing sessions.
In real-world testing, this battery consistently powered a 40V cordless lawn mower through ¾ acre on a single charge, even in difficult terrain.
It maintains stable voltage output and features optimized thermal management, ensuring consistent power delivery during sustained use.
Key Features:
- Genuine OEM Lithium-Ion battery.
- Capacity: 4.0Ah.
- Charge Time: 1 hour (rapid) or 2 hours (standard).
- Warranty: 3 Years.
Pros:
- Genuine OEM product with superior firmware integration and safety protocols.
- 3-year warranty provides excellent peace of mind.
- Fast 1-hour charge time minimizes downtime.
- 4-LED fuel gauge offers precise charge visibility.
Cons:
- Lower capacity compared to third-party 6.0Ah options.
- Higher cost per Ah (Amp-hour) compared to budget alternatives.
- Not ideal for users needing marathon runtimes.
2. MAFACBAC 40V 6.0Ah Replacement Battery (Best Budget Friendly)
For budget-conscious users, the MAFACBAC 29472 40V 6.0Ah battery is described as a runtime game-changer.
This high-capacity lithium-ion replacement offers 50% more capacity than Greenworks’ own 4.0Ah OEM pack, often at less than half the price.
The 6.0Ah rating translates to real-world gains, especially when powering energy-hungry tools like 21-inch cordless mowers.
During testing, this MAFACBAC model powered a Greenworks G-MAX mower through just over an acre of mixed grass, substantially outperforming the stock 4.0Ah battery.
It is best suited for DIYers unwilling to pay premium OEM rates and who prioritize raw value and endurance over seamless integration. It charges fully in about 2.5 hours with a standard 40V charger, which is respectable for its size.
Key Features:
- High-capacity 6.0Ah Lithium ion battery.
- Compatibility: Greenworks G-MAX 40V Lawn Mower Tools.
- Certifications: FCC, RoHS, and CE compliant.
- Warranty: 12-month warranty.
Pros:
- Offers 6.0Ah high capacity at a very low cost.
- Provides long runtime, allowing extended mowing sessions.
- Consistent voltage output suggests quality cell construction.
- One of the most cost-effective ways to boost 40V system productivity.
Cons:
- Lacks a precise multi-LED fuel gauge (users must estimate charge).
- Inconsistent tool communication was noted in testing.
- Firmware compatibility issues may affect charge indicator accuracy on some tools.
3. Qwenoer 40V 6.0Ah Upgrade BMS Battery (Best for High Capacity)
The Qwenoer 40V 6.0Ah Upgrade BMS Battery stands out by featuring an upgraded Battery Management System (BMS) and premium A-grade 18650 cells.
Engineered as a direct replacement for GreenWorks G-MAX tools, it delivers twice the runtime of a standard 2.0Ah pack, making it ideal for heavy-duty lawn care. This model offers robust safety features and real-time monitoring via an LED indicator.
The integrated intelligent chip effectively prevents overheating and voltage drops, even under full load.
In performance tests, it powered a 40V mower through over an acre of dense grass. Compared to the genuine Greenworks 4.0Ah, the Qwenoer offers double the capacity for less than half the price, presenting a compelling upgrade for those seeking performance. It is perfect for users wanting high-capacity power without breaking the bank.
Key Features:
- Capacity: 6000mAh (6.0Ah) Lithium-ion.
- Upgraded BMS and multiple safety protections (e.g., over-charge, over-heating).
- LED charge indicator is available.
- Uses premium A-grade 18650 cells.
Pros:
- Exceptional 6.0Ah high-capacity for extended runtime.
- Advanced BMS ensures safety and prevents voltage drops.
- Delivers premium features at a mid-range price point.
- 180-day replacement warranty policy.
Cons:
- Occasional tool communication lag was noted.
- Not compatible with Gen 1 Greenworks tools.
- Lacks the long-term durability, proof, and warranty of OEM options.
4. Fhybat 2-Pack 6.0Ah Battery (Best Value 2-Pack)
The Fhybat 2-pack 6.0Ah batteries redefine value, offering the ultimate solution for large properties or multi-tool users who need an uninterrupted workflow.
With dual 6.0Ah units, this twin-pack setup allows users to mow, trim, and blow without downtime—simply swapping and going.
This pack provides 3X the capacity of a standard 2.0Ah battery. The batteries feature a 4-level LED indicator and a heat-dissipating design with cooling heat-release holes to ensure both usability and longevity.
In real-world use, having a second battery meant zero interruptions, and the design features short-circuit and over-temperature protections.
Compared to a single OEM Greenworks 4.0Ah battery, this 2-pack delivers triple the total capacity at a lower cost per Ah. It’s a robust system upgrade for serious homeowners.
Key Features:
- Capacity: 6000mAh (6.0Ah) per battery (comes in a 2-pack).
- Includes multiple safety protections (short-circuit, over-temperature, over-charge).
- Features a 4-level LED charge indicator.
- Built with cooling heat-release holes.
Pros:
- Outstanding 2-pack value for continuous, non-stop use.
- Delivers triple the total capacity compared to a single OEM 4.0Ah battery.
- Impressively robust build quality and safety features.
- Eliminates the biggest pain point of cordless systems: downtime.
Cons:
- Slower overall charging time compared to OEM.
- Does not support rapid charge systems.
- Firmware is not always recognized by all tools.
5. 2 Pack 6.0Ah Lithium Battery (Best for Long Runtime)
Engineered for non-stop yard work, this 2 Pack 6.0Ah Lithium Battery set is the top pick for large lawn owners where long runtime and dual-battery convenience are essential.
With 240Wh of energy per battery, this duo powers through thick grass and extended trimming easily. The precise interface and onboard 4-LED fuel gauge ensure smooth integration.
An excellent cooling design, featuring surrounding exothermic holes, enhances cooling during heavy use, which helps reduce thermal throttling.
Field testing showed each battery lasting up to 80 minutes on a 40V mower, potentially covering an acre or more depending on conditions. This dual-pack strategy effectively eliminates downtime by letting users swap batteries while the other charges.
Key Features:
- Capacity: 6000mAh (6.0Ah) per battery (comes in 2 Packs).
- Features a 4-LED power display (onboard fuel gauge).
- Includes a dual protection chip for safety.
- Excellent cooling design with exothermic holes.
Pros:
- Maximum endurance and continuous use due to the dual-pack 6.0Ah capacity.
- Offers more than triple the total capacity of the Greenworks 4.0Ah single battery.
- Compliant with CE, FCC, and RoHS safety standards.
- Marathon sessions are possible with zero interruptions.
Cons:
- Critical limitation: Not compatible with the 21-inch MO40L02 mower.
- Does not support rapid charging.
- Some firmware quirks may affect charge indicators on certain tools.
6. Amitself 4.0Ah Replacement Battery (Best Mid-Range Option)
The Amitself 4.0Ah Replacement Battery hits the sweet spot between affordability and reliability, offering OEM-equivalent capacity at a significant discount.
Delivering the same runtime as the official Greenworks pack, it can cost less than 40% of the price. It is a no-frills, high-value solution, perfect for budget-savvy homeowners with mid-sized yards.
With 4,000mAh of lithium-ion power, the Amitself pack features a 3-LED indicator, providing a clear readout of charge levels. In testing, it matched OEM performance, powering a 40V mower through ¾ acre of grass.
The intelligent protection system prevents voltage spikes and overheating. It is fully compatible with second-gen tools and is ideal for users who need reliable, consistent power without the overkill of a 6.0Ah battery.
Key Features:
- Capacity: 4.0Ah.
- Compatibility: Greenworks 40V GMAX Power Tools (Gen 2 only).
- Features a 3-LED indicator.
- Intelligent protection system.
Pros:
- Offers OEM-matching 4.0Ah capacity at a much lower cost.
- Provides reliable and consistent power, matching OEM runtime.
- 12-month quality guarantee and 24-hour customer service support.
- Intelligent protection features are similar to OEM safety systems.
Cons:
- Does not offer a 6.0Ah capacity option.
- Not compatible with older Gen 1 tools.
- Lacks the extensive 3-year warranty of the genuine Greenworks pack.
Choosing the Right Greenworks 40V Battery for Your Lawn Mower: A Detailed Buying Guide
The battery is the core of your Greenworks 40V lawn mower, and selecting the correct one significantly affects runtime, performance, and overall cost. Here is a breakdown of the key features to consider before you buy:
Amp-Hour (Ah) Rating: Runtime and Power
The Amp-Hour (Ah) rating is the most important factor, as it directly determines how long your lawn mower can operate on a single charge. Higher Ah means less interruption for recharging and more efficient lawn care.
- 2.0Ah: This capacity is generally suitable for light-duty tasks and smaller yards. It offers the shortest runtime but is typically the most affordable option.
- 4.0Ah: This provides a good balance for medium-sized yards, offering a noticeable increase in runtime compared to the 2.0Ah models. The Greenworks Genuine 4.0Ah battery is frequently viewed as the best “all-around” choice.
- 6.0Ah: Ideal for large yards or demanding tasks like cutting thick grass, the 6.0Ah capacity maximizes runtime. However, expect to pay a premium for this maximum capacity.
Compatibility: Ensuring a Proper Fit
While Greenworks batteries are often backwards compatible, you must always verify compatibility with your specific mower model.
- Generation 1 vs. Generation 2: Some older Greenworks tools (Gen 1) may not work with newer battery designs. You should check the battery listing or your mower’s manual for compatibility information.
- Voltage Match: It is essential to ensure the battery is specifically rated at 40V. Using the incorrect voltage can potentially damage the battery or your tool.
Battery Type and Build Quality
All Greenworks 40V batteries use Lithium-Ion technology, which is prized for its high energy density, low self-discharge, and lack of memory effect.
Cell Quality and BMS: The quality of the internal battery cells dictates performance and lifespan. Look for batteries that mention high-quality cells, such as “Top A 18650 cells”.
Furthermore, a strong Battery Management System (BMS) is vital for safety, protecting the battery from overcharging, short circuits, and overheating, which extends its life.
Additional Features
- LED Fuel Gauge: This is a very convenient feature that provides a quick visual indication of the remaining battery charge, allowing you to monitor usage easily.
- Warranty: A robust warranty provides peace of mind; Greenworks Genuine batteries often offer a 3-year warranty.
- Price and Alternatives: Third-party brands like Qwenoer, MAFACBAC, Fhybat, and Amitself offer budget-friendly alternatives to the Genuine Greenworks options. However, reliability and lifespan may vary compared to OEM products.