Black+Decker LST136 Weed Whacker Review: 40V Power Meets Precision Edging

1. Introduction: The Cordless Trimmer Landscape

For decades, homeowners faced a frustrating dilemma when it came to maintaining the edges of their lawns. You either dealt with the ear-splitting noise, noxious exhaust, and temperamental carburetors of a gas trimmer, or you fought the endlessly tangling, restrictive extension cords of an electric model. The battery-powered revolution changed all of that, and Black+Decker has consistently been at the forefront of accessible residential lawn care.

Our focus in this exhaustive Black+Decker LST136 Weed Whacker review is on a machine that attempts to hit the “sweet spot” for the average homeowner. Boasting a robust 40V MAX lithium-ion battery system, an Automatic Feed Spool (AFS), and the unique ability to seamlessly convert into a wheeled edger, the LST136 promises professional-looking results without the commercial-grade price tag.

If you are currently evaluating your options and looking at comparing corded, cordless, and gas lawn trimmers, this deep dive will dissect every element of the LST136 to determine if it is the right tool to elevate your weekend yard maintenance.

2. Unboxing & First Impressions

Right out of the box, the Black+Decker LST136 conveys a sense of sleek, lightweight agility. The signature orange and black design is familiar, but the inclusion of the bulky 40V MAX battery pack at the rear signals that this isn’t your grandfather’s underpowered 18V tool.

Assembly: Putting the unit together takes less than five minutes. It essentially involves snapping the guard into place over the trimmer head, attaching the auxiliary handle, and sliding the battery into the docking port. No tools are required, which is a massive plus for those who want to get straight to work.

What immediately stands out is the weight—or rather, the lack thereof. At just 7.8 pounds with the battery installed, the LST136 is remarkably lightweight. This minimal heft is crucial for homeowners who suffer from back or shoulder fatigue when lugging around heavy gas-powered equipment.

3. The 40V MAX Battery & PowerCommand Dial

The heart of the LST136 is its 40V MAX lithium-ion battery. Historically, battery trimmers struggled to offer both raw power and sustained runtime. Black+Decker solves this engineering hurdle with a brilliant feature: the PowerCommand Dial.

Located conveniently on the handle, the PowerCommand dial acts as an adjustable throttle limit. It gives you the flexibility to choose between two distinct operational modes (and anywhere in between):

• Max Power (Setting 6): Ideal for chewing through thick, neglected patches of crabgrass or dense weed stalks. The motor spins at maximum RPMs (up to 8,500 RPM). The trade-off? The battery will drain in approximately 20 to 25 minutes.
• Max Runtime (Setting 1): Perfect for weekly maintenance trimming around garden beds, fences, and mailboxes. The motor RPMs drop to a gentler 6,500 RPM, which easily extends the battery life to 40 to 45 minutes on a single charge.

Furthermore, the 40V battery includes a built-in state-of-charge indicator. Pushing a button reveals a series of green LEDs that let you know exactly how much juice is left before you start a large project. When learning the basics of lawn care 101, establishing a consistent trimming routine is vital, and knowing your exact battery life prevents frustrating interruptions.

4. Cutting Performance & Automatic Feed Spool (AFS)

The LST136 utilizes a 13-inch cutting swath. While commercial gas trimmers often push 15 or 16 inches, 13 inches is an excellent “Goldilocks” size for residential use—wide enough to clear large areas quickly, but narrow enough to maneuver between tight landscaping rocks and fragile flower beds.

However, it is important to manage expectations. This trimmer is designed for residential grass and standard weeds. If you are trying to understand how to get rid of weeds without killing grass, this tool offers the precision needed. But, if you are attempting to clear heavy, woody brush, thick blackberry vines, or thick saplings, the 0.065-inch line will snap rapidly. It is a weed whacker, not a brush cutter.

5. 2-in-1 Versatility: Trimmer to Edger Conversion

A beautifully cut lawn looks messy if the edges along the driveway and sidewalks aren’t crisp. Usually, this requires purchasing a secondary, dedicated lawn edger. The Black+Decker LST136 circumvents this by offering 2-in-1 functionality.

By simply twisting the collar on the aluminum shaft, the entire trimmer head rotates 180 degrees. What makes this implementation superior to competitors is the inclusion of a sturdy metal edge guide wheel. Instead of awkwardly hovering the spinning line over the concrete, you rest the wheel directly on the pavement and walk it along the edge of the grass like a unicycle.

This design creates a perfectly straight, professional-looking trench between your turf and your driveway, rivaling the finish of much more expensive precision lawn tools.

6. Ergonomics, Weight, and Usability

Black+Decker paid close attention to user comfort with the LST136. Beyond its sub-8-pound weight, the tool is highly customizable to fit the operator’s body.

• Telescopic Shaft: The straight aluminum shaft features a quick-release clasp that allows you to lengthen or shorten the tool. Whether you are 5’2″ or 6’4″, you can adjust the trimmer to ensure you are standing upright, preventing lower back pain.
• Adjustable Auxiliary Handle: The secondary handle on the shaft can be moved up, down, or rotated. This allows you to find the perfect center of gravity, ensuring the trimmer feels balanced and doesn’t pull downward on your wrists.
• Quiet Operation: Because it is battery-powered, the noise level is drastically lower than a 2-cycle gas engine. You won’t need heavy-duty ear protection, and you can edge your lawn early on a Sunday morning without infuriating your neighbors.

7. Competitor Comparison: Black+Decker vs. Greenworks vs. Worx

How does the LST136 hold up against the fierce competition in the mid-tier battery trimmer market?

While the Worx model is lighter, its 20V battery lacks the torque of the Black+Decker. The Greenworks offers comparable 40V power, but the lack of a wheeled edger gives the LST136 a distinct advantage for homeowners who prioritize perfectly manicured sidewalks.

8. Pros and Cons: The Final Summary

9. Who Should Buy the LST136?

The Black+Decker LST136 is specifically engineered for a targeted demographic.

It is perfect for: Homeowners with a quarter-acre to half-acre lot who want a lightweight, zero-maintenance tool. If you hate mixing gas, loathe dragging extension cords around, and despise bumping the trimmer head to feed line, this machine will feel like a massive breath of fresh air. It is particularly excellent for elderly users or those with back issues due to its low weight and telescopic adjustments.

It is NOT for: Landscaping professionals, owners of massive rural acreage, or people clearing overgrown, neglected fields. The 0.065-inch line and 40V motor simply aren’t designed to chew through miles of thick brush.