Battery Platforms
How long do yard tool batteries take to charge?
Charge time is a property of the charger, not the battery. Two Greenworks packs of the same size differ by 90 minutes.
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.
Nobody shops for a charger. You buy a mower, and the charger in the box quietly decides whether a lawn you cannot finish in one pass costs you forty minutes or two and a half hours. Every one of those figures is published; almost nobody puts them next to each other.
Every published charge time, converted to a rate
| Tool | Pack | Watt-hours | Charge time | Rate (Wh/min) |
|---|---|---|---|---|
| Greenworks 80V LM2108S mower | 80V 4.0Ah | 320Wh | 40 min | 8.0 |
| Greenworks 80V ST80L210 trimmer | 80V 2.0Ah | 160Wh | 30 min | 5.3 |
| Greenworks 80V BL80L02 blower | 80V 2.5Ah | 200Wh | 40 min | 5.0 |
| EGO ST1521S trimmer | 56V 2.5Ah | 140Wh | 50 min | 2.8 |
| Toro 21356 mower | 60V Max 6.0Ah | 324Wh (published) | 150 min | 2.2 |
| Greenworks 40V LM2054 mower | 40V 4.0Ah | 160Wh | 120 min | 1.3 |
Watt-hours are volts x amp-hours using each brand's advertised pack voltage, except Toro's, which the manufacturer publishes directly. Charge times are the manufacturer's own published figures for the charger supplied in that kit.
Look at the two Greenworks mowers. The 80V flagship charges 320Wh in 40 minutes; the 40V push mower charges half that energy in three times the time. Same brand, same year, same catalogue. The pack is not the variable — the charger in the box is.
Why a rate is more useful than a time
A charge time only tells you about one pack. A rate tells you about every pack you will ever put on that charger, including the bigger one you buy in three years. It is the single most portable number in this whole comparison, and no manufacturer publishes it.
The mow-wait-mow arithmetic
If your lawn needs more energy than the pack holds, you are not really buying a runtime, you are buying a duty cycle: the share of the time you are outside that the mower is actually cutting.
This is why the Greenworks 40V push mower is honestly rated to a third of an acre and no more: not because it lacks power, but because the recovery time makes anything bigger an all-day job. If that is your lawn size, check the LM2054 on Amazon — it is the right tool and the charge time never becomes your problem. If your lawn is larger, read how many batteries you actually need before you buy anything.
A spare pack beats a fast charger
Two 320Wh packs and a slow charger will always beat one 320Wh pack and a fast charger, because the spare removes the wait rather than shortening it. Kobalt builds this straight into the machine with two 80V bays and 640Wh installed; Ryobi ships two 6.0Ah packs in the mower kit for the same reason.
The spare pack is also the one that survives. Nobody publishes a cycle-life figure for these batteries, so the pack you rotate is doing half the cycles of the pack you run flat every week. We work through what is and is not published about pack lifespan on the battery life page.
The handheld tools charge fastest, and it matters least
The fastest charge time we found anywhere is 30 minutes, on the Greenworks 80V string trimmer's 2.0Ah pack — a tool that only claims 45 minutes of runtime in the first place. The EGO POWERLOAD trimmer publishes 50 minutes to charge 140Wh, a slower 2.8Wh per minute, but on the platform where that same pack also runs your blower and pole saw.
Handheld charge times are the least consequential numbers on this page, because trimming and edging are jobs you finish inside one pack. Spend your attention on the mower charger. That is the one that decides whether your Saturday has a two-hour hole in it. The Greenworks 80V flagship is the fastest-charging mower we have a published figure for, and the EGO POWERLOAD trimmer is the one whose pack does the most other jobs.
Sizing a charger to your lawn
The question that matters is not "how fast does it charge" but "does the charger keep up with the job". Those are different questions and only the second one ruins an afternoon.
| Your lawn | Energy needed | One pack enough? | What the charger has to do |
|---|---|---|---|
| Up to 1/3 acre | ~270Wh | Yes on most kits | Nothing during the job |
| 1/3 to 1/2 acre | ~450-600Wh | Marginal | Recover one pack while you finish |
| 1/2 to 1 acre | ~600-1,000Wh | No | Full recharge mid-job, or a second pack |
| Over 1 acre, walk-behind | 1,000Wh+ | No | Two packs minimum; the charger is not the answer |
Energy figures are our arithmetic from published runtime claims and mowing-time estimates by lawn area. See the sizing guide for how those are derived.
Both machines cut the same lawn. One does it in an hour and a half, the other takes an afternoon, and the only difference is the charger in the box. That is the case for reading this spec before you buy rather than after.
What we cannot tell you
- Whether the published time is to 100% or to 80%. No manufacturer states which, and lithium charging slows dramatically at the top of the range. The rates above are directional between brands, not laboratory comparisons.
- Charge time in the cold. Not published by anyone here, and temperature genuinely affects it.
- How charging habits affect pack life. Neither EGO, Greenworks, Ryobi nor Kobalt publishes a cycle-life figure on the pages we cite, so we do not have a sourced answer.
- Ryobi and Kobalt mower charge times. Not published on the product pages we work from. Kobalt states an approximate 60 to 90 minutes for its pair of 4.0Ah packs and nothing more precise.
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.
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.
Toro 60V Max 21" Recycler Self-Propel (21356)
Toro · Toro 60V Max Flex-Force · Our score 8.3/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
The only manufacturer here that publishes the actual watt-hour figure for its pack -- and the number tells you something the others hide.
Published specs
| Model | 21356 |
|---|---|
| Deck | 21 in, 14-gauge steel |
| Battery | 60V Max L324, 6.0Ah, 324Wh |
| Charge time | 150 min |
| Runtime claim | Up to 45 min on the 6.0Ah |
| Drive | Personal Pace variable-speed RWD |
| Weight | 66 lb |
| Storage | SmartStow vertical |
Source: 60V Max 21 in. Recycler Self-Propel Lawn Mower (21356T), toro.com
Toro labels the pack 60V Max 6.0Ah and publishes 324Wh. 324 / 6.0 = 54V -- the nominal voltage, not the 60V max-charge figure on the sticker. Every brand's 'max volts' is roughly 11% above nominal, so a nameplate watt-hour number is always about 11% optimistic. This is the single most useful spec on this page.
What the numbers favor
- Publishes a real watt-hour figure (324Wh) instead of leaving you to multiply the marketing voltage
- 45 minutes from 324Wh, against Greenworks' 33 minutes from a nameplate 320Wh
- 14-gauge steel deck, the only steel deck spec published on this page
- SmartStow vertical storage -- a genuine constraint solver in a one-car garage
What they don't
- 150-minute recharge is the slowest here by a wide margin
- Toro's 60V line is narrower than EGO's or Ryobi's, so the platform grows less far
you are buying into a platform rather than a mower. Toro builds excellent mowers; the 60V Flex-Force tool range is not the one to bet a decade of yard tools on.
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 40V 20" Push LM2054
Greenworks · Greenworks 40V · Our score 8.0/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
40 minutes on a 160Wh pack and 57.5 lb to push -- the honest answer for a third of an acre and nothing more.
Published specs
| Model / SKU | LM2054 / 2549902 |
|---|---|
| Deck | 20 in |
| Max blade speed | 3200 RPM |
| Battery included | 40V 4.0Ah |
| Cut height | 1.2-3.6 in, 7 positions |
| Runtime claim | Up to 40 min |
| Weight | 57.5 lb |
| Rated for | Up to 1/3 acre |
| Warranty | 3-yr tool / 3-yr battery |
Source: 40V 20" 4-in-1 Push Lawn Mower (LM2054), greenworkstools.com
40V x 4.0Ah = 160Wh. Note it claims 40 minutes on 160Wh where the 80V flagship claims 33 minutes on 320Wh -- a 20 in deck and no self-propel drive motor is why.
What the numbers favor
- Lightest published weight on this page at 57.5 lb, and the only sub-60 lb mower here
- Claims 40 minutes from 160Wh -- the best published minutes-per-watt-hour of any mower on this page
- Same 3200 RPM blade speed as the 80V flagship
- 4-in-1 deck at the entry price
What they don't
- Push only -- no drive assist on any slope
- 1.2 in minimum cut height is lower than most cool-season lawns should ever be cut
- 120-minute recharge, three times the 80V model's 40 minutes
your lawn is over a third of an acre or has any real slope. Greenworks rates it to 1/3 acre and you will be pushing all 57.5 lb of it up the hill yourself.
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.
EGO Power+ 15" POWERLOAD Carbon Fiber ST1521S
EGO · EGO 56V ARC Lithium · Our score 8.9/10
#ad No verified live price right now, so we show none rather than a stale one. How we're funded.
A lifetime shaft warranty and a head that reloads line at the push of a button -- the two things that actually go wrong with a string trimmer.
Published specs
| Cutting swath | 15 in |
|---|---|
| Line | 0.095 in dual-feed spiral twist |
| Head | POWERLOAD automatic winding |
| Shaft | Carbon fiber, split shaft |
| Battery (kit) | 56V 2.5Ah |
| Runtime claim | Up to 30 min on 2.5Ah |
| Charge time | 50 min |
| Warranty | 5-yr tool / 3-yr battery, lifetime shaft |
Source: POWER+ 15" POWERLOAD String Trimmer with Carbon Fiber Shaft, egopowerplus.com
56V x 2.5Ah = 140Wh. 30 minutes of published runtime from 140Wh is about 4.7Wh per minute -- roughly a quarter of what a blower on turbo burns.
What the numbers favor
- Lifetime warranty on the carbon fiber shaft, published
- POWERLOAD winds the line for you -- the job everyone hates
- 0.095 in line, the heavier of the two common home gauges
- Split shaft, so it takes EGO's multi-head attachments
What they don't
- Ships with the small 2.5Ah pack; 30 minutes is a modest published runtime
- EGO does not publish a weight for this configuration
you only edge a short driveway. An 8 in edger attachment on a power head you already own does that job better and costs a fraction.
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.
Where to buy the tools on this page
Every link below is an Amazon affiliate link. We show no price we have not verified today, so where there is no live figure the link says "check price" and takes you to the listing to read it there.
Best published spec sheet
Greenworks 80V 21" 4-in-1 LM2108S
Greenworks · Greenworks 80V
Best published watt-hour honesty
Toro 60V Max 21" Recycler Self-Propel (21356)
Toro · Toro 60V Max Flex-Force
Best for small yards
Greenworks 40V 20" Push LM2054
Greenworks · Greenworks 40V
Best overall
EGO Power+ 15" POWERLOAD Carbon Fiber ST1521S
EGO · EGO 56V ARC Lithium
#ad As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. How we're funded.
Common questions
How long does a lawn mower battery take to charge?
Why do two batteries the same size charge at different speeds?
Can I mow, charge and finish the same afternoon?
Is it better to buy a second battery or a faster charger?
Should I leave the battery on the charger?
Sources
- Greenworks 80V 21" 4-in-1 Self-Propelled Mower (LM2108S), greenworkstools.com
- Greenworks 40V 20" 4-in-1 Push Lawn Mower (LM2054), greenworkstools.com
- 60V Max 21 in. Recycler Self-Propel Lawn Mower (21356T), toro.com
- EGO POWER+ 15" POWERLOAD String Trimmer, egopowerplus.com
- Greenworks 80V Cordless 16" String Trimmer (ST80L210), greenworkstools.com
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.
- 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.
- How many batteries do you actually need?
Lawn size to watt-hours to pack count, plus the sequential-versus-simultaneous distinction.
- Best battery lawn mowers of 2026
Six flagship battery mowers ranked on watt-hours in the box and energy spent per minute.