I have a love/hate relationship with string trimmers. As an organic gardener, it is a great tool to cut things that you can't pull (or too tired to pull as in my case ). The love comes from the fact that in a few minutes I can obliterate so much vegetation. The hate comes from the aggravations of using them:
1. Gas operated. I have a high-power wheeled string trimmer. This thing is a beast and cuts through anything. The problem is, it cuts through anything! It routinely breaks sprinkler heads and such. It is also a handful at times although for cleaning massive amount of brush, it is a godsend.
2. Corded electric. I have had a few of these. They ones I have are the cheaper ones and they never perform well. But even if they did, dragging that long cord is just not practical.
3. Cordless electric. I bought the Black and Decker (18v?) Lithium one a couple of years ago. I have four batteries for it. And the darn thing goes through all of them before I am done. It also lacks power severely. Anything but the thinnest vegetation causes it to bog down. Tall grass also wraps around unit and doesn't get cut.
Faced with two houses with 1+ acre lots, I went looking for something new and landed on this latest string trimmer from Stihl: http://www.stihlusa.com/trimmers/FSA85.html
It comes in two variations, the FSA65 and FSA85. I got the latter as it has a longer straight shaft and 14 inch cutting circle instead of 13. And variable speed. Cost difference is only $40.
The big story is this: power, power, power. The unit is whisper quiet while not cutting. So you immediately think it is a wimp. But push it toward whatever you need cut and the thing roars and cuts like there is no tomorrow. It is as if it get angry when something resists being cut! The tone becomes lower (but still no where near too loud) and it tears things up including thick weeds that are quarter inch thick.
I suspect the unit has internal feedback/servo control to maintain speed and torque and hence the reason that there is no slow down whatsoever.
Battery life is excellent. I got the smaller batter as it was $100 cheaper and the high-power charger gets it to full charge in 30 minutes, and 80% in 20 minutes. It is startling how fast the charger gets it back up. No sooner than you finish a beverage resting between cutting and you can do it again.
The unit is designed to go 95% of the way at full speed and power. For the last 5%, it seems to slow down a bit and then it stops. It never has the gradual drop that Black and Decker has which sadly, starts almost as soon as you use it. For almost entire charge of the battery, you have the same aggressive power I explained above.
I managed to cut 12+ inch tall grass around our entire yard of 1 acres before the battery gave out.
I never had variable speed in a trimmer and thought it would be of no use. But it is surprisingly useful. I can run slow near tree trunks and delicate objects. Running slower also sharply increases battery life.
The string head is a dual unit with bump feed. I find that I can't always get it to feed after I bump but once I start cutting, it then pulls the string out.
Yes, it is still work cutting things. But as grass trimmers go, this thing is so darn near perfect.
Now the bad news. The trimmer is $300 (the smaller one is $250). The high-speed charger is $89 (standard one is $49). The smaller battery is $150. The large capacity one is, are you sitting?, $260! My complete system set me back ~$520.
That is one heck of a lot of money to spend on a trimmer compared to $30 units. What can I say, good things in life aren't always cheap . For the amount of yard maintenance I do, it is well worth it. So much so that I might get a second one for the other house!
If you are dealing with smell, noise and vibration of two-stroke trimmers or are tired of dragging a cord with you, you should give this a try. It is the best innovation I have seen in string trimmers.