Battery Platforms
Greenworks 80V vs Kobalt 80V: same voltage, different bets
Identical on the sticker. One ships 320Wh and a half-acre rating; the other ships 640Wh across two bays and claims a full acre.
Affiliate disclosure: we earn a commission if you buy through our links, at no extra cost to you. It never changes which product we rank first — here is how we're funded.
We have not tested these units. Every spec on this page comes from the manufacturer's own documentation and is linked to it. Every computed figure is arithmetic you can redo. Prices are checked daily — last verified January 1, 1970. Here is exactly how we pick.
These two mowers wear the same voltage badge and are not close to being the same purchase. Kobalt ships twice the energy and claims twice the acreage. Greenworks ships a documented warranty and a spec sheet you can actually read. Which matters more depends on whether you are buying a mower or joining a platform.
Side by side
| Spec | Kobalt 80V SP | Greenworks LM2108S |
|---|---|---|
| Deck | 21 in, steel | 21 in |
| Batteries in the kit | 2 x 80V 4.0Ah | 1 x 80V 4.0Ah |
| Installed watt-hours | 640Wh | 320Wh |
| Published runtime | Up to 80 min | Up to 33 min |
| Acreage rating | Up to 1 acre | Up to 1/2 acre |
| Drive | RWD, 7 speed settings | Variable-speed RWD |
| Blade speed | Not published | 3200 RPM |
| Weight | Not published | 75 lb |
| Recharge | Approx. 60-90 min | 40 min |
| Warranty | Not published on listing | 4-yr tool / 4-yr battery |
| Where to buy | Lowe's (house brand) | Widely available |
Sources: Kobalt 80V self-propelled mower listing and Greenworks LM2108S, both checked 3 September 2026.
The energy gap, worked out
Two things are true here. Kobalt gives you twice the energy, and it also appears to use it slightly more efficiently per minute — though a 21-inch deck with turbo leaf pickup (the Greenworks) legitimately draws more than a conventional one, so this is not a defect on the Greenworks side.
The platform question
A mower comparison and a platform comparison give different answers here.
As a mower, the Kobalt is the stronger buy for a large lawn: more installed energy, seven drive speeds, a steel deck and a one-acre rating.
As a platform, the picture changes. Kobalt is a Lowe's house brand, which means one retailer controls availability, pricing and how long replacement packs stay on shelves. When you buy the mower you are betting that a specific retailer keeps supporting a specific voltage line for a decade. That bet is not unreasonable — Kobalt 80V has been running for years and all its 80V packs are cross-compatible across the outdoor range — but it is a narrower bet than one on a brand sold through many channels.
Greenworks also asks you to read carefully: it runs 24V, 40V, 60V and 80V as entirely separate platforms. Buying "a Greenworks" commits you to nothing until you check which line the tool sits on. That trips people up constantly, and it is the first thing we cover in the battery compatibility guide.
What each brand will tell you
Greenworks publishes blade RPM, weight, recharge time and a warranty on both tool and battery. The Kobalt listing publishes runtime, acreage and drive speeds but not weight, cut-height range, noise or warranty terms.
We are not going to fill those gaps with estimates. A 21-inch steel-decked self-propelled mower with two 4Ah packs aboard is obviously not light, but "obviously not light" is not a specification and we will not print a number nobody published. If weight matters to you — and on a self-propelled mower it matters less than people assume, because the drive motor moves it — ask in store before you buy.
The verdict
Choose Kobalt 80V if
- Your lawn is between a half acre and an acre
- You want to finish without touching a charger
- You shop at Lowe's anyway and that is where you will buy packs
Choose Greenworks 80V if
- You want a published 4-year battery warranty
- You want to compare on specs rather than on floor impressions
- A 40-minute recharge suits how you mow
- You want the tool available from more than one retailer
If your lawn is over an acre, neither of these is the right shape of answer — look at electric riding mowers instead, where the watt-hour math changes completely.
The products discussed
Specs are the manufacturer's own and linked to the page they came from. Prices come from a live daily check; where we have no verified price we say so rather than print a stale one.
Kobalt 80V Max 21" Self-Propelled (dual-port)
Kobalt · Kobalt 80V Max · Our score 8.4/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
Two 4Ah bays, 80 published minutes and an acre rating -- the most runtime per purchase of any 80V walk-behind here.
Published specs
| Deck | 21 in, steel |
|---|---|
| Motor | Brushless |
| Batteries included | 2 x 80V 4.0Ah (dual port) |
| Runtime claim | Up to 80 min |
| Rated for | Up to 1 acre |
| Drive | Self-propelled RWD, 7 speed settings |
| Recharge | Approx. 60-90 min |
Source: Kobalt 80-Volt 21-in Self-propelled Battery Mower (2 batteries), lowes.com
80V x 4.0Ah = 320Wh per pack; two bays = 640Wh installed. Kobalt's listing does not state whether the two ports discharge simultaneously or in sequence, so we do not claim either -- what is verifiable is that 640Wh is on the machine when you start.
What the numbers favor
- 640Wh installed across two bays, the most of any walk-behind on this page
- Rated to 1 acre, twice the Greenworks 80V flagship's half-acre rating
- Seven published speed settings on the self-propel drive
- All Kobalt 80V packs are cross-compatible across the 80V outdoor line
What they don't
- Sold through Lowe's only, so availability and price track one retailer
- The listing does not publish weight, cut-height range or a noise figure
- Kobalt's 80V outdoor range is narrower than EGO's or Ryobi's
you want a platform rather than a mower. Kobalt is a single-retailer house brand -- fine for the tool, thinner as a decade-long ecosystem bet.
How it scores
Scores are our editorial weighting of the published specs above, not a test result. They are deliberately kept out of this page's structured data.
Greenworks 80V 21" 4-in-1 LM2108S
Greenworks · Greenworks 80V · Our score 8.4/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
The only mower here that publishes motor wattage, blade RPM, weight and an acreage rating -- and the only one whose battery warranty matches its tool warranty.
Published specs
| Model / SKU | LM2108S / 2550402 |
|---|---|
| Deck | 21 in |
| Max blade speed | 3200 RPM |
| Battery included | 80V 4.0Ah |
| Cut height | 1.38-4.0 in, 7 positions |
| Runtime claim | Up to 33 min |
| Weight | 75 lb |
| Rated for | Up to 1/2 acre |
| Warranty | 4-yr tool / 4-yr battery |
Source: 80V 21" 4-in-1 Self-Propelled Lawn Mower (LM2108S), greenworkstools.com
80V x 4.0Ah = 320Wh, using Greenworks' advertised pack voltage.
What the numbers favor
- 4-year battery warranty -- a year longer than EGO's 3-year, on the component that fails first
- Publishes blade RPM, weight and acreage rating; the other two brands publish none of the three
- 40-minute recharge on the included charger, the fastest published here
- 4-in-1 deck adds turbo leaf pickup on top of mulch, bag and side discharge
What they don't
- 320Wh included, the least of the three flagships -- and the 33-minute runtime claim reflects that
- 75 lb is the only published weight here, and it is not light
you want one battery to finish a half-acre without a swap. Greenworks rates the mower for 1/2 acre but claims only 33 minutes on the included pack; those two numbers only reconcile if you buy a second battery.
How it scores
Scores are our editorial weighting of the published specs above, not a test result. They are deliberately kept out of this page's structured data.
Common questions
Are Greenworks 80V and Kobalt 80V batteries interchangeable?
Which 80V mower runs longer?
Is Kobalt only sold at Lowe's?
Does a bigger acreage rating mean a better mower?
Which has the better warranty?
Sources
Read next
- Battery Platforms
Pick the system once and the next four tools are decided for you. Start here.
- 40V vs 80V: what the voltage on the sticker actually buys you
Volts x amp-hours = watt-hours. The one calculation that makes every battery spec comparable.
- EGO 56V vs Greenworks 80V: higher voltage, smaller pack
80V beats 56V on paper. The included pack sizes reverse the result, and here is the math.
- Best battery lawn mowers of 2026
Six flagship battery mowers ranked on watt-hours in the box and energy spent per minute.
- Best electric mower for a half acre to an acre
Half an acre and up, runtime is the whole problem. Ranked on installed watt-hours and acreage rating.