KUNLUN 40V 6.0Ah Lithium-ion Replacement Battery for Greenworks G-MAX 40V 29472 29462 29252 20202 22262 Cordless Power Tools and Lawn Mower NOT for Gen 1 Review

Overview

This isn’t a lawn mower itself, but the KUNLUN 40V 6.0Ah replacement battery is a critical upgrade for anyone running a Greenworks G-MAX 40V cordless mower or tool system. Designed as a drop-in replacement for several popular Greenworks models (29472, 29462, 29252, 20202, 22262), it offers a higher capacity than the stock 4.0Ah batteries many of those mowers shipped with. It’s best for Greenworks owners who want longer run time without buying a whole new tool, but it’s critical to note it’s not compatible with first-generation Greenworks 40V tools.

Who Should Buy This

• Homeowners with 1/4 to 1/2 acre lawns who own a Greenworks G-MAX mower – If your stock battery dies before the yard is done, this 6.0Ah pack buys you 30–50% more cutting time per charge.
• Greenworks tool collectors – If you already own a string trimmer, blower, or chainsaw in the G-MAX line, this battery can power all of them, saving you from buying multiple packs.
• Budget-conscious buyers who want OEM-like performance for less – At $39.99, this is typically $10–20 cheaper than Greenworks-branded 4.0Ah batteries, yet delivers more capacity.
• Anyone whose original battery has degraded – Older Greenworks batteries lose capacity over time. This is a direct, affordable replacement to revive an otherwise good mower.

Key Features Breakdown

• 40V 6.0Ah Capacity – That’s 240 watt-hours, roughly 50% more than the common 4.0Ah pack. In practice, expect 45–60 minutes of mowing on a typical 1/4-acre lawn, versus 30–40 minutes with a stock battery. For trimmers and blowers, you’ll get a full yard of work without swapping.
• Lithium-ion Chemistry – No memory effect, low self-discharge over winter storage, and consistent power output until the battery is nearly dead. You won’t get the power fade that older NiCad packs suffer from.
• Compatibility: NOT for Gen 1 – This is the most important spec. If your Greenworks mower or tool was made before roughly 2015 (Gen 1 models have a different battery mount), this will not fit. Check your model number carefully—29472, 29462, 29252, 20202, and 22262 are confirmed compatible.
• LED Charge Indicator – A small button and four LED lights on the battery let you check remaining charge at a glance. Simple but useful for deciding if you need to swap packs before starting a job.
• Overcharge/Discharge Protection – Built-in circuitry prevents the battery from being damaged by overcharging or draining too low. This extends overall lifespan, especially if you tend to leave batteries on the charger overnight.

Pros

1. More run time than stock – The 6.0Ah capacity is a genuine upgrade over the 4.0Ah packs that ship with most Greenworks mowers. You’ll finish a medium lawn on a single charge.
2. Direct drop-in replacement – No adapters, no wiring. It clicks into the same battery slot and uses the same charger as your existing Greenworks packs.
3. Good value per watt-hour – At roughly $0.17 per watt-hour, this is significantly cheaper than buying a new Greenworks-branded battery of similar capacity.
4. Works across multiple tools – If you have a Greenworks G-MAX trimmer, blower, or chainsaw, this battery powers them all. One battery serves your whole yard tool fleet.
5. LED charge indicator is genuinely useful – Unlike some generic batteries that skip this feature, the KUNLUN has it, making it easy to grab a fully charged pack before heading outside.
6. No performance lag on high-draw tools – This battery delivers consistent voltage even under load. Your mower won’t bog down or cut out when the grass gets thick, unlike some cheaper aftermarket packs.

Cons

1. Not compatible with Gen 1 tools – If you have an older Greenworks mower from before the G-MAX series launched, this battery won’t physically fit. Double-check your model number before buying.
2. Build quality isn’t quite OEM – The plastic casing feels slightly thinner than a genuine Greenworks battery. It’s durable enough for normal use, but a hard drop might crack the housing.
3. No carrying handle – The battery lacks a built-in handle or grip, making it slightly awkward to carry or pull out of the mower compared to some competitors.
4. Run time claims are optimistic – In real-world mowing with thick grass or damp conditions, expect closer to 45 minutes than the 60+ minutes some sellers advertise. Still an improvement over stock, but don’t expect miracles.

Bottom Line

The KUNLUN 40V 6.0Ah battery is a smart, cost-effective upgrade for anyone already invested in the Greenworks G-MAX ecosystem. It delivers noticeably longer run time than the standard 4.0Ah pack, works across multiple tools, and costs less than OEM replacements. The main caveat is compatibility—this is strictly for newer G-MAX models, not Gen 1 tools. If your mower is compatible, you’ll get a reliable, high-capacity battery that extends the life of your cordless equipment without breaking the bank. It’s not quite as rugged as a factory Greenworks battery, but for the price, it’s an excellent value.

Frequently Asked Questions

Will this battery work with my Greenworks 40V mower from 2013?
Probably not. If your mower is a Gen 1 model (typically pre-2015), it uses a different battery mounting system. This battery is designed for G-MAX series tools. Check your mower’s model number—if it matches 29472, 29462, 29252, 20202, or 22262, you’re good. If not, measure the battery slot to confirm.

Can I use this battery with my Greenworks 40V charger?
Yes. It’s compatible with the standard Greenworks 40V charger that came with your mower or tool. The charge time from empty is roughly 2–3 hours, about the same as a 4.0Ah pack due to the higher capacity.

Will this battery fit in my Greenworks string trimmer?
If your trimmer is a G-MAX model (like the 21062 or 21262), yes. The battery uses the same slide-in interface as all Greenworks G-MAX 40V tools. It’s physically larger than a 4.0Ah pack but fits the same slot.