The big news in the battery-powered garden tools sector may be the advancing tech that allows for higher voltage tools. Battery voltage for weed eaters seems to be going to infinity and beyond. The weed eater that won my informal whack-a-thon was an 80 volt machine. 80 volt weed eaters break new ground in the “high voltage” string trimmer space. The evolution in cordless power tools in general has been marked not only by steady improvements in battery chemistry, but also by continual increases in the battery voltage these tools run on… from the first 4.8V cordless drills in the early 1960s, to the 18V cordless tools in the 2000’s, to the 20V+ cordless power tools of today. The first of these trimmers I purchased was a 20V unit. Soon after I learned there were 40V versions of the garden tools, then 60V versions, and finally I discovered the king of the hill 80V line.
Steve Bakker, Is It Time To Ditch That Loud, Polluting, Hard-To-Start, Smelly, Obnoxious Gas-Powered Weed Whacker?, CleanTechnica, September 23, 2018.