Pros / You can adjust the power output level to conserve battery life or get the extra performance you need.

Cons / The 25-minute battery life is short.

 Verdict / The LST136 is an excellent cordless trimmer with a 13-inch cutting path. Because you can adjust the power level to your needs, it is an ideal trimmer for yards with different kinds of grass and weeds.

The LST136 has a 13-inch cutting path and enough battery life to last up to 25 minutes, providing enough power to cut the toughest weed and clear a decent path to reduce the time you spend doing yard work.

Trimmer Design

The Black & Decker LST136 weighs just 7.8 pounds with the battery installed. This is an average weight for a battery-powered grass trimmer, and much lighter than a gas engine trimmer. The heaviest model we reviewed was the Green 21142, at nearly 10 pounds.

The shaft height of this weed whacker is adjustable, allowing you to set its height to a comfortable level, saving your back and arms from unnecessary pain. The LST136's trimmer head rotates, allowing you to convert this trimmer into an edger. A built-in guide helps keep your edging straight, and it flips up out of the way when the unit is in trimming mode. This dual function reduces the need for multiple tools and saves you time.

Power & Battery

This electric grass trimmer uses a 40-volt lithium-ion battery. These batteries are lightweight and the recharge time is around an hour, which is a quick recharge time.

Black & Decker's 40V MAX battery is interchangeable with other 40V MAX tools such as the hedge trimmer, lawn vacuum and sweeper. This system enables you to use the same battery with these other tools, giving you the option of purchasing the tools without a battery for less. An even better advantage is that you can rotate out the discharged battery with a fresh one from another tool if you need more time to work on your yard.

You can adjust the cutting speed using a dial on this weed eater. This is a handy feature, as it makes it possible to conserve power when you don't need a full-strength cut or get a boost of power to tackle tough weeds and thicker vegetation. The trimmer includes one battery and a charger unit. The battery runs up to 25 minutes on a medium power setting, which is not great.

String Features

The LST136 features an automatic line feed, removing the need to bump the trimmer against the ground to advance the line. The line advances when it encounters resistance as you trim the grass and weeds in your yard. Replacing and rewinding the spool is not difficult at all, and detailed instructions are illustrated in the owner manual. The only thing you really need to do is wind the line without too much overlapping. This helps eliminate tangles.

This trimmer model uses a single line, and Black & Decker recommends using a string 0.065 inches in diameter when replacing. You can order a new spool and line from the Black & Decker website, but you can also purchase a roll of string from your local hardware store and rewind it yourself. The Black & Decker LST136 has a wide cutting path of 13 inches, allowing your line to trim more at once.

Warranty & Support

Black & Decker backs up this device with a three-year warranty that covers defective parts and materials. This is significantly longer than the standard one-year warranty most manufacturers offer. The Black & Decker website offers plenty of useful information about the trimmer, including a downloadable user manual in case you lose yours. The manual walks you through the installation of the shield and the procedure of replacing your string spool, among other things.

Most often, manufacturers do not provide adequate repair options or parts, forcing you to purchase another product. Fortunately, Black & Decker gives you the option of fixing your trimmer or replacing parts yourself. You can order parts online from the website, as well as locating an authorized repair center with the service center locator tool on the website.

Black & Decker LST136 Visit Site
  • Total Weight
  • Number of Lines
  • Cutting Path
  • Length of Warranty
  1. How much the trimmer weighs with the battery installed.
    Less is better.
  2. 1  Black & Decker
    7.8 Pounds
  3. 2  RYOBI
    6.65 Pounds
  4. 3  WORX
    7.7 Pounds
  5. Category Average
    6.67 Pounds


If you are ready to switch over from a noisy, gasoline-powered weed trimmer, the Black & Decker LST136 is the best electric string trimmer we researched. With its powerful 40-volt battery, wide cutting path, variable power settings and automatic line feed, you can trim and edge your grass and weeds without the harmful emissions and weight of a gas-powered trimmer. It’s a versatile trimmer with adjustable height and a rotating head for edging.

Black & Decker LST136 Visit Site

Specifications and Benchmarks

Trimmer Design

Total Weight (pounds)
Edging Position
Edging Guide
Adjustable Shaft Length
Starter Safety Device
Cord Retainer
Not Applicable

Power & Battery

Not Applicable
Average Battery Run-time (minutes)
Battery Charge-time (hours)
Batteries Included
Interchangeable Battery

Warranty & Support

3 Years
Repair & Service Locator
Phone & Email Support
Owner Manual Download

String Features

Cutting Path (inches)
Recommended Line Diameter (inches)
Number of Lines
Line Feed Type