Friday, July 23, 2010

Cordless electric string trimmers (a.k.a. "weed whackers")

Table of Contents

Important note: if you have a question to ask, please ask it at Lawn Mower Forum, either in the Black & Decker area or the Electric & Battery Operated area at that website. I apologize for being unable to handle individual requests for help posted on this blog or sent by email.
"In my next blog I plan to discuss cordless electric string trimmers to augment the pollution-free, low-noise mowing experience."

I wrote that about 3 months ago,  as I wrapped up my blog entry on mower batteries.  After much procrastinating here is my experience choosing and using a cordless string trimmer.

Not using a corded string trimmer

Before getting our cordless trimmer, my wife and I did own a plug-in version for several years.  It was a perfectly good trimmer from Black and Decker -- but having to get out, and later put away, the 100 foot extension cord was enough of a deterrent that it only got used 2 or 3 times per season.  My routine was to avoid using it by being as diligent as possible with the mower around the lawn's edges, and just letting the grass get tall around our more delicate plantings.  It finally dawned on us that we should own either a string trimmer that actually gets used, or none at all.

Choosing a string trimmer

The first step in choosing a cordless string trimmer is whether to go with a NiCd or a lithium battery model.  My experience with other cordless power tools has nudged me towards lithium, and for primarily two reasons.  (1) lithium batteries are newer technology, and superior to NiCd (longer life, longer run time, lighter weight, holds charge longer when not in use) and (2) chargers provided with lithium tools tend to be better than the ones provided with NiCd tools, in terms of not overcharging and damaging the battery -- at least this is true of the NiCd tools I currently own.  Of course, you do have to pay more for a lithium trimmer, but it really is worth it.  A friend of ours who owned a cordless NiCd string trimmer complained that it would not run very long before the battery needed recharging.

After an internet search I found 3 lithium battery models to choose from.  This site has a comparison of the Worx GT WG151 and the Troy-Bilt TB57, and there is also the Black and Decker LST1018.  The customer reviews of the Worx GT seemed more favorable than the others, and I liked that it was available with a fast 30-minute charger.  (It's also available with a slower 3-5 hour charger, so if you buy it make sure you are getting the one you want.)  So in the end I ordered the Worx fast-charging model.

By the way, I generally make a point of checking out customer reviews at whenever spending this kind of money ($150.00 in this case) on a power tool, and recommend that you do so as well.

Using the string trimmer, pros and cons

First, and briefly, the obvious benefits: not as loud as a gas-powered trimmer (but noticeably louder than an electric mower), and no power cord to contend with.  It's nice to have something I can quickly grab from the closet -- yes, that's where we keep it -- and touch up the yard after a mowing.

I was also pleased to discover that the Worx trimmer automatically shuts off when the battery charge gets low, thereby preventing battery damage from deep discharging.    I don't know if the other string trimmers I looked at have this feature, but it does seem to be an all-too-common problem among cordless mowers.

Now for my main complaint. This trimmer can put a strain on your back if you let it.  That was my experience the first two times I used it.  And the second time, I really overdid things by using it for about 1/2 hour (that's when the battery needed recharging), and then for another 15 or 20 minutes after a quick recharge.  My back was noticeably stiff the following day, though not in a debilitating way. Since then, I have learned to limit each use to about 20 minutes or less, and to switch between a left-handed and a right-handed grip every 5 minutes or so; I have had no problems since adopting this practice.  As a result having the fast charger is not really a bonus, though owners of larger yards might still find that feature useful.

A minor complaint is that I apparently don't get how to use the edging feature. The head can be rotated so that the string cuts vertically, rather than horizontally, making a nice clean edge along a sidewalk for example.  But the handle must be held at an awkward angle when doing this, whereas our old corded trimmer did edging much more easily.

All in all I'm glad we have a cordless trimmer and so far am quite happy with it, in spite of the two drawbacks I discuss above.
Update - posted 25 Dec. 2010

After about a month into owning the Worx GT WG151 string trimmer, the battery died suddenly last August.  As it was under warranty, Worx replaced it for free, for which I am thankful.

I did not use the trimmer a whole lot for the rest of the season, so we will have to wait and see if the new battery holds up better than the first one did.  If I had it to do over, I would have gotten the slower-charging version of this trimmer, as I wonder if the fast 30-minute charger might be too hard on the battery.  I am surprised that a lithium battery failed so quickly; hopefully it was just a defective battery and not indicative of a systemic problem.


  1. My black and decker fire storm nicad trimmer power pack died after six years of use. I think it has only 500 charging cycles. How many charging cycles can lithium battery provide?

  2. Important note:

    If you have a question to ask, please ask it at Lawn Mower Forum, either in the Black & Decker area or the Electric & Battery Operated area at that website. I apologize for being unable to handle individual requests for help posted on this blog or sent by email.

    Link to Lawn Mower Forum's main page:

    From there you'll find the Black & Decker section (under "Brand Specific Forums" and the Electric & Battery Operated section.

    Best regards,



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