Battery Platforms
Are EGO batteries interchangeable? And will they work with Ryobi?
Two questions people ask constantly and almost nobody answers in a straight line. Here are the straight lines.
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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.
Are EGO batteries interchangeable?
EGO states this compatibility on its own product pages — the 24-inch hedge trimmer page says it works with all EGO ARC Lithium batteries, and the 8-inch edger attachment page publishes a separate runtime for the 4.0Ah, 5.0Ah, 7.5Ah and 10.0Ah packs. Those four published numbers are the compatibility claim, proven.
That flat draw is worth understanding. On a light tool, buying a bigger pack converts almost linearly into more time. On a hungry tool near its current limit it does not, because the tool is working the pack harder. This is why the same pack behaves differently on a trimmer and a mower.
Do EGO batteries work with Ryobi?
The same answer applies to every other cross-brand pairing people ask about: EGO to Greenworks, Ryobi to Kobalt, Greenworks to DeWalt. Cordless tool platforms are deliberately closed. The pack is where the margin lives, and no manufacturer has any reason to let you buy someone else's.
The trap: same brand, different platform
Cross-brand incompatibility surprises nobody. What genuinely catches people out is incompatibility inside one brand.
| Brand | Separate platforms | Share packs? |
|---|---|---|
| Ryobi | 18V ONE+ and 40V | No |
| Greenworks | 24V, 40V, 60V, 80V | No -- four separate platforms |
| EGO | 56V ARC Lithium | Yes -- one outdoor platform |
| Kobalt | 24V and 80V Max | No -- but all 80V packs share across the 80V outdoor line |
Compiled from each manufacturer's own product pages, checked 3 September 2026. Check the voltage on the tool page before every purchase; ranges change.
Greenworks is the one to watch. Four voltage lines under one brand name means "I'll stick with Greenworks" is not a platform decision at all — you can own four Greenworks tools and four incompatible chargers. If you go Greenworks, pick the voltage line first and treat the brand name as incidental. We compare the 80V line specifically in EGO vs Greenworks and Greenworks vs Kobalt.
EGO is the simplest of the four: one outdoor platform, one pack family, everything fits. That simplicity is a genuine part of what you are buying.
Third-party adapters
You can buy adapters that physically mate one brand's pack to another's tool. We would not put one on a mower, and here is the reasoning rather than just the warning.
- They break the conversation. A modern pack and tool exchange data about current limits, cell temperature and state of charge. An adapter passes power and drops the conversation, so the pack's protection can no longer see what the tool is doing.
- The load is not trivial. A mower under thick grass is pulling several hundred watts continuously. That is the worst possible place to remove thermal protection.
- Both warranties end. The tool's and the pack's. On a platform where the battery warranty is 3-4 years and the packs are the expensive part, that is a poor trade.
On a work light or a small fan, the stakes are low and people do it happily. On anything with a blade, buy the right pack.
Practical rules
- Pick the voltage line, not the brand. "Greenworks" is not a platform; "Greenworks 80V" is.
- Buy tools 2 through N bare. Kits bundle a pack and charger you already own. This is the single biggest avoidable cost on any platform.
- Size packs to the hungriest tool. A pack that satisfies the mower satisfies everything else. The reverse is not true.
- Keep one small pack. A 2.0-2.5Ah pack makes a trimmer or hedge trimmer noticeably lighter to hold at arm's length, and that is a real quality-of-life difference on a long hedge.
- Check compatibility on the manufacturer's page, not the retailer's. Retailer listings mix voltage lines together in search results constantly.
If you are still deciding which line to commit to, that decision is the whole job of the platform guide. Once packs are on your shelf, making them last is the next thing worth reading.
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.
EGO Power+ 21" Select Cut LM2135SP
EGO · EGO 56V ARC Lithium · Our score 9.1/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
The most watt-hours in the box of any flagship walk-behind here, on the platform with the widest tool range to grow into.
Published specs
| Deck | 21 in |
|---|---|
| Cutting torque | Up to 7.0 ft-lbs |
| Battery included | 56V 7.5Ah |
| Cut height | 1-4 in, 8 positions |
| Self-propel speed | 0.9-3.1 MPH |
| Runtime claim | Up to 60 min |
| Warranty | 5-yr tool / 3-yr battery |
Source: EGO POWER+ 21" Select Cut System (LM2135SP), egopowerplus.com
56V x 7.5Ah = 420Wh, using EGO's advertised pack voltage.
What the numbers favor
- 420Wh in the box -- the largest included pack of any flagship walk-behind on this page
- Eight cut-height positions from 1 to 4 in, the widest published range here
- Three interchangeable lower blades (mulching, high-lift bagging, extended runtime)
- 5-year tool warranty, the longest published on this page
What they don't
- EGO publishes torque (7.0 ft-lbs), not motor wattage, so it cannot be compared directly against Greenworks' 1500W figure
- The 7.5Ah pack that earns the runtime claim is also the expensive one to replace
your yard is under a quarter acre. You would be paying for 420Wh of headroom you will never discharge, and a 20 in push mower cuts the same grass.
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.
Ryobi 40V HP Brushless 21" Self-Propelled
Ryobi · Ryobi 40V · Our score 8.6/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
Two 6Ah packs and the longest published runtime claim on this page, on the platform with the cheapest route to a fourth and fifth tool.
Published specs
| Model | RY40HPLM01B |
|---|---|
| Deck | 21 in |
| Motor | Brushless, 40V HP |
| Batteries included (kit) | 2 x 40V 6.0Ah |
| Drive | Variable-speed rear-wheel self-propel |
| Runtime claim | Up to 80 min on 2 x 6Ah |
Source: 40V HP Brushless 21" Self-Propelled Mower, ryobitools.com
40V x 6.0Ah = 240Wh per pack; the kit ships two, so 480Wh total -- but only 240Wh is available at any moment, because the mower draws one pack at a time.
What the numbers favor
- 480Wh across two packs, the most total energy in any kit here
- Two packs means you swap and keep mowing instead of waiting on a charger
- Ryobi's 40V range is the broadest consumer battery line of the three platforms
What they don't
- Only one 240Wh pack is live at a time -- the 480Wh is sequential, not simultaneous
- Ryobi does not publish a cut-height range or weight on the product page, so both are unknown to us
you own nothing on Ryobi yet and expect to buy heavy tools later. 40V is the lowest voltage of the three platforms, and the ceiling shows on chainsaws and riding gear.
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 EGO batteries interchangeable?
Do EGO batteries work with Ryobi tools?
Can I use a Ryobi 18V ONE+ battery in a Ryobi 40V tool?
Are all Greenworks batteries the same?
Are third-party battery adapters safe?
Sources
Read next
- Battery Platforms
Pick the system once and the next four tools are decided for you. Start here.
- How long do electric lawn mower batteries last?
Runtime per charge is arithmetic. Lifespan in years is mostly warranty terms and honest uncertainty.
- EGO 56V vs Ryobi 40V: which platform should you start on?
420Wh in one pack against 480Wh in two, with the warranty and build-out cost worked out.
- 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.
- Are battery lawn mowers worth it?
Yes under about an hour of mowing, no above it without a second pack. The conditional answer.