LawnMaster
LawnMaster CLMF4821A: 48V MAX Self-Propelled Cordless Lawn Mower
The LawnMaster CLMF4821A delivers gas-free performance with a 48V MAX brushless motor and four included lithium-ion batteries, offering up to 48 minutes of runtime on a 21-inch deck. Rear-wheel drive self-propulsion and 3-in-1 discharge flexibility make it a genuinely capable machine for yards up to half an acre.
It's an ideal fit for suburban homeowners who want the freedom of cordless mowing without sacrificing cutting performance.
As an Amazon Associate, we earn from qualifying purchases. This does not affect our analysis or recommendations.
Last updated: . Based on our analysis of 364 lawn mowers.
What Sets It Apart
Key specification highlights based on our analysis.
3-in-1 Discharge
Mulch, side discharge, and rear bag (59 of 364 mowers have all three)
Rear-Wheel Drive
Better traction on hills and slopes vs front-wheel drive
Considerations
Polymer Cutting Deck
Lightweight but less durable than steel; won't rust
Why We Recommend It
- 01.
Four 24V 4.0Ah lithium-ion batteries included , dual charger lets you keep a pair charging while the other pair runs, extending effective runtime beyond the rated 48 minutes
- 02.
Brushless motor delivers efficient power with longer motor life and quieter operation versus brushed alternatives
- 03.
Rear-wheel drive self-propulsion provides better traction on mild hills and slopes compared to front-wheel-drive models
- 04.
6-position central cutting height adjustment spans 1.4 to 3.4 inches , one lever changes all four wheels simultaneously
- 05.
Zero oil changes, no spark plugs, no fuel , low maintenance ownership means more time mowing, less time wrenching
Considerations
- 01.
48-minute rated runtime means large or heavily overgrown lawns may require mid-job battery swaps even with four batteries
- 02.
Polymer deck, while rust-proof and lightweight, is less impact-resistant than steel decks and may show wear sooner with heavy use
- 03.
Cutting height tops out at 3.4 inches, which may not be enough for homeowners who prefer a taller cut for drought-resilient lawns
Technical Specifications
| Feature | Specification |
|---|---|
| Mower Type | Self propelled |
| Power Source | Battery |
| Cutting Width | 20" |
| Deck Material | Polymer |
| Blade Type | Rotary |
| Cutting Height | 1.4" – 3.4" |
| Height Positions | 6 |
| Battery | 48V 4Ah |
| Runtime | 48 min |
| Drive | Rear wheel |
| Discharge | 3-in-1 (Mulch, Side, Bag) |
| Weight | 44 lbs |
Power & Performance
The 48V MAX brushless motor (configured as two 24V batteries in series) generates strong, consistent power without the RPM drop-off common in brushed motors under load. Brushless technology also converts more energy into cutting force rather than heat, which translates to better runtime efficiency from each lithium-ion battery charge.
The result is capable performance through standard residential grass , fine fescue, bluegrass, and moderate-height lawn grasses , though very thick or wet turf will tax the system more.
Cutting System
The 21-inch polymer rotary deck covers a solid swath per pass, balancing maneuverability in tighter yards with enough width to reduce total passes on open lawns. Polymer construction eliminates rust and keeps the overall weight at 44 lbs, making it easier to handle than comparable steel-deck machines.
Six central cutting height positions between 1.4 and 3.4 inches adjust all wheels in a single motion, and the 3-in-1 discharge system , mulching, side discharge, and rear bagging , covers virtually every seasonal cutting scenario.
Drive & Handling
Rear-wheel drive self-propulsion is a meaningful differentiator here: by driving the rear wheels, the mower maintains forward traction even when the front wheels climb over uneven ground or mild slopes, a known weakness of front-wheel-drive cordless mowers. At 44 lbs, the machine is manageable to push or guide around obstacles without feeling flimsy.
The folding handle aids storage and transport, though yard size up to 1/2 acre means the self-propel system will get a genuine workout.
Battery / Fuel
The four included 24V MAX 4.0Ah lithium-ion batteries pair in sets of two to deliver 48V to the motor, with the dual charger letting you replenish one pair while the other is in use , a smart system that minimizes downtime. Rated runtime is approximately 48 minutes per battery set, which covers smaller yards in a single pass and gives medium-sized yards a fighting chance with a quick mid-job swap.
Because there's no gas, no oil, and no carburetor to worry about, the entire maintenance routine is limited to cleaning the deck and occasionally checking blade sharpness.
Who Is This Mower For?
Ideal For
- ✓ Homeowners with yards up to 1/2 acre (21,780 sq ft) who want cordless freedom without managing gas, oil, or pull-cord starts
- ✓ Eco-conscious users wanting zero direct emissions and quieter operation , brushless motor runs significantly quieter than gas engines
- ✓ Buyers with moderately hilly or uneven terrain who need rear-wheel drive traction that front-wheel-drive cordless mowers can't provide
- ✓ Homeowners who want discharge flexibility , the 3-in-1 mulch/side/bag setup handles seasonal needs without buying attachments separately
Not Ideal For
- ✕ Owners of large properties over 1/2 acre where even four lithium-ion batteries may not complete the job in one charge cycle
- ✕ Users with very thick, tall, or overgrown grass that demands sustained high-RPM cutting power closer to commercial gas equipment
- ✕ Those needing a cut above 3.4 inches , warm-season grass enthusiasts who mow at 4+ inches will hit the ceiling on this mower's height range
Assembly is straightforward and requires no special tools , most users report getting the mower ready in under 30 minutes by attaching the handle sections and connecting the battery pack. The push-button start eliminates any pull-cord frustration from the very first use.
Charge all four batteries fully before the first mow so you have maximum runtime available from the start
Clip the bag attachment into place before starting if you plan to bag , switching discharge modes mid-mow is easier with the mower off and on level ground
Warranty terms for the LawnMaster CLMF4821A should be confirmed directly with LawnMaster or the retailer at purchase, as coverage for the motor, batteries, and deck may vary by region. Lithium-ion battery warranties are commonly separate from the main unit , verify both before buying.
FAQ
How long do the batteries last on the LawnMaster CLMF4821A?
LawnMaster rates the battery system at up to 48 minutes of runtime per charged battery set. Since four lithium-ion batteries and a dual charger are included, you can keep one pair charging while the other is in use , effectively doubling your available runtime if needed.
Real-world results vary based on grass thickness, terrain, and self-propel usage.
Is the LawnMaster CLMF4821A truly self-propelled, and does it work on hills?
Yes , it's a rear-wheel drive self-propelled mower, which gives it better hill traction than front-wheel-drive models. Rear-wheel drive pushes from behind the mower's center of gravity, maintaining grip on mild slopes where front-wheel-drive units can lose traction.
It's rated adequate for hilly terrain, though steep grades will still require extra effort.
Can the LawnMaster CLMF4821A mulch, bag, and side discharge?
Yes , it supports all three discharge modes, making it one of only 59 mowers (out of 364 reviewed) to include full 3-in-1 functionality. Mulching recycles clippings into the lawn as fertilizer, side discharge clears thick grass quickly, and the rear bag collects clippings for easy disposal.
You can switch modes as your lawn conditions change throughout the season.
How big of a yard can the LawnMaster CLMF4821A handle?
LawnMaster rates this mower for yards up to 1/2 acre (approximately 21,780 sq ft). The 21-inch cutting deck and self-propelled drive keep fatigue low on larger lawns, and four batteries give you enough power to tackle that coverage area.
Yards significantly over 1/2 acre may require longer charging breaks between battery sets.
Does the LawnMaster CLMF4821A require much maintenance compared to a gas mower?
Maintenance is dramatically reduced versus gas , there's no oil to change, no spark plugs to replace, no carburetor to clean, and no fuel to stabilize over winter. The push-button start means no pull-cord failures either.
Routine care is limited to cleaning the deck after each use and keeping the blade sharp seasonally.
Is the polymer cutting deck on the LawnMaster CLMF4821A a problem?
Polymer decks are lighter and completely rust-proof, which are genuine advantages , the 44 lb total weight is partly thanks to the deck material. The trade-off is that polymer is less impact-resistant than steel, so hitting rocks or hard debris may cause cosmetic damage more easily.
For a typical residential lawn kept clear of debris, it performs reliably and without corrosion concerns.
Bottom Line
The LawnMaster CLMF4821A earns its place as a compelling cordless upgrade for gas mower refugees: four lithium-ion batteries, a dual charger, rear-wheel drive self-propulsion, and 3-in-1 discharge flexibility come together in a package rated for up to 1/2 acre. It won't replace a commercial gas machine for heavy-duty work, but for the eco-conscious suburban homeowner who wants the freedom of battery-powered mowing with real performance behind it, this is a strong value proposition.
Those with very large properties or a need to cut at heights above 3.4 inches should look at alternatives.
Best for suburban homeowners with up to 1/2 acre of flat-to-mildly-hilly lawn who want cordless freedom, zero emissions, and discharge flexibility without buying batteries separately.
Consider alternatives if your yard exceeds 1/2 acre, you need a cutting height above 3.4 inches, or you're tackling consistently thick or overgrown grass that demands sustained gas-level power.
Check Price on AmazonAs an Amazon Associate, we earn from qualifying purchases. This does not affect our analysis or recommendations.