Kobalt 80V String Trimmer First Impressions
You always want to buy the best lawn mower for your needs. The Kobalt KST 140XB 80V String Trimmer offers solid value for an above-average performance product. Next, we'll also share our experience with Kobalt's 80V blower and chainsaw. Now, though, let's talk about string trimmers.
Assembly is very simple. All it takes is a screwdriver to securely install the trimmer guard in place. The mounting bracket has been improved compared to the previous model due to the use of metal parts. In fact, we noticed several improvements over last year's 40V cord trimmer, which should help improve durability and ergonomics.
Kobalt KST 140XB Cordless Weed Wacker Design and Features
The Kobalt 80V Cord Trimmer features a straight shaft design with an adjustable cutting range from 14 inches to 16 inches. You'll need that screwdriver again, but just turn the cord cutter in the opposite direction to shorten your queue. Why do you want to do this? Less wire means less power to turn the same RPM and better run time. So if your yard is less stressed, choose shorter lines for greater efficiency. Kobalt's newest trimmer is an impact-feed, refillable, dual-wire concept filled with the recommended 0.080" monofilament wire. This is higher than the 0.065" line at 40V.
One of the new design innovations places the motor in the middle of the shaft above the connection point. This has two wonderful consequences. First, the position of the motor provides near perfect balance when the battery is in place. The balanced weight prevents a lot of the arm fatigue I've experienced in the past with unbalanced trimmers. The Kobalt KST 140XB 80V String Trimmer is now also easily attached. We certainly know that most 40V models have a hard time even thinking about running an edger attachment, but it looks like the Kobalt has now drawn the line. Kobalt does not yet offer its own accessories. However, the coupling is universal and should accept most off-the-shelf third-party options.
Kobalt KST 140XB Build Quality
Also, if you choose to use attachment points for slings (not included), that is now also an option. It is a plastic construction reinforced with metal at the pinch points. We'll have to wait and see how it holds up against the Florida sun. The handle has a textured rubber area for a comfortable non-slip grip. The on/off button and speed mode button are located at thumb length for easy access with the push of a button. A green LED light indicates which mode you are in, the default is low speed.
To save battery power, the device will turn off after 1 minute if left on and not in use. Overall, I found the length and weight to be just right for my 5'7" height. Editor-in-Chief Kenny Koehler also visited the department. At 6'2" he also found a comfortable handling setup. Well, it's as cozy as you'd expect when it's 95 degrees outside.
Kobalt 80V String Trimmer Performance

How much practical performance does 80 volts have? Quite a lot, I have to say. Last year, I thought 40 volts would be enough for the job (and it was), but 80 volts is just another level! If more power is needed to tackle denser overgrown areas, the change from low speed to high speed is quite noticeable. The low speed setting is 5,000 RPM and the high speed setting is 5,500 RPM. Bump-feeding, the dual-line system performed admirably as expected and was easy to refill after reading the instructions.
The 0.080-inch trim line lends confidence and durability to those overgrown areas along the chain link fence line. Battery consumption will vary based on speed setting, outside temperature and strip cut length. Based on my testing, a fully charged battery was sufficient at low speeds and occasionally high speeds to mow the perimeter and interior features of my 0.48-acre lawn.
One question remains about performance, will it drive in the driveway? Last year's model was designed to allow it, but it was really awkward. While it is possible to turn the Kobalt 80V String Trimmer from side to side, it is clearly not designed for this capability. If you can't live without that perfect edge look, then you'll want an edger attachment.

Kobalt 80V String Trimmer Specifications
- Power: 80V, 2.0 amp hour battery pack
- Charging time: 30 minutes
- Recommended yard size: 0.5 – 1 acre
- Shaft Design: Straight
- Cutting Tape: 16"
- Wire diameter: 0.080 inches
- Feed system: double-line convex point
- Weight: 13.22 lbs
- Warranty: 5 years
- Price: $116 (tools only), $233 (kit)
Conclusion and Final Thoughts
The Kobalt 80-Volt Corded Trimmer is good enough for basic pruning needs and sometimes for some heavy-duty pruning. While the Kobalt is approaching professional-grade performance, it (like nearly everyone else) lacks enough runtime to get through a professional gardener's day. Battery life will vary with speed settings and temperature. However, once it's cool enough, the battery will fully charge in 30 minutes. This model feels well balanced and able to accept different attachments. Best of all it runs quietly with almost no vibration.
Build quality is good enough for a homeowner and it should be able to handle your trimming needs on a 1/2 acre. Homeowners with 3/4 to a full acre of low-stress mowing to do will find this a good option, too. As with all Kobalt OPEs, you can find the Kobalt 80V String Trimmer at Lowe's.

A quick note on OPE and its proper use. Or maybe I should let my 15 month old tell you what not to do. During assembly, my son sneaked up on it, jumped on it, and grabbed the handle while making his best maneuvering noises. My first thought was "durability test". Then I took a closer look. Hmm… the Force is very strong…