SUNTEK SLM4521A Battery Powered Self-Propelled Lawn Mower (21-Inch, 40V, 4.0Ah Battery, App Compatible)
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MEDIOCRE
55
Winnowl Index
Winnowl Verdict
Our product audit of the SUNTEK SLM4521A Battery Powered Self-Propelled Lawn Mower positions it at a MEDIOCRE (60) Winnowl Index, where the price and capability sit at or above average. The Fair Value index combined with the 40 brand strength from SUNTEK and an Average Performance rating is a balanced purchase. The Total Run Time of 68 minutes is above the 52.85 and means you should have plenty of power to handle larger yards or overgrown grass that would typically drain a standard battery, while on the lower end the Battery Voltage is below the class average and may mean you should effectively maintain blade speed on a tidy, dry lawn that gets mowed on a regular schedule. We recommend staying with this purchase; it captures 6% better cost to Performance than the standard entry in this class.
Market Value Index
Mediocre
$629.99
Overpriced
Fair
High Value
At $629.99, you’re capturing 6% more Performance per dollar than the $658.14 average, which confirms its Fair Value.
Performance Rating
Average
With an Average Performance rating, the Total Run Time of 68 minutes suggests you should have plenty of power to handle larger yards or overgrown grass that would typically drain a standard battery, though the Battery Voltage at 40 V might occasionally mean you should effectively maintain blade speed on a tidy, dry lawn that gets mowed on a regular schedule.
Brand Strength
Average
The Average Brand Strength of SUNTEK comes from Mediocre Brand Trust in the Battery Powered Self-Propelled Lawn Mowers class.
Available At
$629.99
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The Winnowl Lab Report
| Specification | Value | Rating | Vs. Average | Winnowl Insight |
|---|---|---|---|---|
| Battery Voltage | 40 V | Mediocre | 29% worse | Standard residential power. Balanced for consistent performance on well-maintained suburban lawns. |
| Usable Energy Capacity | 256 Wh | Mediocre | 36% worse | |
| Warranty | 3 Years | Mediocre | 22% worse | Standard residential protection. Covers the machine through the initial years of typical seasonal use. |
| Total Run Time | 68 minutes | Average | 18% better | High-endurance rating. Provides a safety buffer for thick grass or larger properties. |
| Charging Time | 60 mins | Average | 39% better | Standard residential charge rate. Balanced for typical weekly maintenance schedules. |
| Total Capacity | 8 Ah | Average | 16% worse | High-capacity power supply that prevents the motor from bogging down or stalling when cutting through thick, heavy grass. |
| Number of Batteries | 2 count | Average | 18% better | Dual-battery loadout. Provides immediate redundancy and extended runtime for larger properties. |
| Cutting Width | 21 inches | Average | Average | Standard residential deck width. Balanced for efficiency and maneuverability through most garden gates. |
| Single Battery Capacity | 4 Ah | Mediocre | 32% worse | |
| Cutting Height Adjustment | 7 settings | Average | Average | High-precision adjustment rack. Allows for fine-tuning based on grass species and regional moisture levels. |
Ranking Factors
Insights
- Value Rank: #53 out of 75.
- Performance Rank: #50 out of 75.
- Winnowl Quadrant: Budget
Strengths
- At mins, the Charging Time is faster than the class average (98.21 mins) but not as fast as some products at (30 mins).
Neutral
- A Total Capacity of Ah is about average 9.55 Ah but below the class max of 24 Ah.
- A Cutting Width of inches is about average (21.21 inches) but narrower than the widest in class at 26 inches.
- A Total Run Time of minutes is about average (57.45 minutes) but not as long as the class max of 150 minutes.
- A Cutting Height Adjustment of settings is about average (7.01 settings) but not as many as the class max of 10 settings.
- battery(s) is about average 1.69count but below the most in class (4 count).
Weaknesses
- The Years warranty is in the bottom 10%, offering minimal long-term protection.
- At V, the voltage is in the bottom 10%, indicating lower power potential than most peers.
Comparison
| Name | Winnowl Index | Value | Performance | Brand | Price | Usable Energy Capacity | Total Run Time | Battery Voltage | Total Capacity | Cutting Width | Warranty | Charging Time | Number of Batteries | Cutting Height Adjustment | Single Battery Capacity |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SUNTEK SLM4521A Battery Powered Self-Propelled Lawn Mower |
MEDIOCRE
55
|
Mediocre | Average | Average | $629.99 | 256 Wh | 68 minutes | 40 V | 8 Ah | 21 inches | 3 Years | 60 mins | 2 count | 7 settings | 4 Ah |
| Kobalt 80-Volt 21-in Self-propelled Battery Lawn Mower |
ELITE
94
|
Exceptional | Strong | Exceptional | $599.00 | 576 Wh | 75 minutes | 80 V | 9 Ah | 21 inches | 5 Years | 60 mins | 2 count | 7 settings | 5 Ah |
| Greenworks 82V 25-Inch Battery Powered Self-Propelled Lawn Mower |
ELITE
86
|
Fair | Strong | Strong | $979.97 | 787.20 Wh | 60 minutes | 82 V | 12 Ah | 25 inches | 4 Years | 30 mins | 3 count | 7 settings | 4 Ah |
| LiTHELi 18-Inch Brushless Self-Propelled Mower |
MEDIOCRE
59
|
Exceptional | Mediocre | Mediocre | $276.59 | 256 Wh | 50 minutes | 40 V | 8 Ah | 18 inches | 5 Years | 120 mins | 2 count | 6 settings | 4 Ah |
Rankings
