Previously, we found that battery-powered chain saws and leafblowers were inadequate if you wanted to do substantive work around your yard. That no longer is the case, because in the past 2 years, manufacturers incorporated brushless motors to add power and torque to battery-powered models.
POWER UP. Nine manufacturers now sell chain saws and leafblowers that run off brushless motors. These models, all of which are powered by high-voltage (36 volts or higher) lithium-ion batteries, typically cost at least $30 more than do similar brushed-motor models.
Brushless motors, which are direct-current motors in which no metal contacts the electrode, have been used for years in the industrial-tool and power-tool sector to achieve higher torque, longer motor life and more energy efficiency. In brushed motors, brushes rub together and produce resistance, which creates the heat and sparks that you see inside of the electric motor. Brushless motors produce no friction. Therefore, brushless motors generate more power and consume less energy than do brushed motors.
“[Friction] makes your battery drain a little faster, so you gain a little bit in performance and a little bit in efficiency with brushless motors,” says Duane Hanselman, who is an associate professor of electrical engineering at The University of Maine.
Most manufacturers say their brushless-motor chain saws deliver performance that’s equal to their similar-size gasoline-powered counterparts. We agree. We found that the brushless-motor chain saws that are on the market are capable of doing the type of yard work that corded electric chain saws and smaller gasoline chain saws are designed to do, such as trimming, removing small trees and cutting limbs of up to 6-1/2 inches in diameter. However, brushless-motor chain saws cost at least $70 more than do their gasoline-powered counterparts.
We didn’t find any notable improvements in air speed among battery-powered leafblowers that have brushless motors. Almost all corded and gasoline leafblowers, which typically cost $30–50 less than do comparable models that have brushless motors, exceed the air-speed performance of the latter. In other words, for clearing wet leaves or clumps of debris from a path, a corded or gasoline model is better.
LET IT RUN. Manufacturers claim that battery-powered chain saws and leafblowers that have brushless motors have longer run times than do models that have conventional motors. However, no industry standard exists for measuring battery life. Most manufacturers have their own proprietary simulations to estimate how long that a model will operate on a single charge and include a rough estimation of a model’s maximum run time in their specification sheets.
Four Amp-Hour Batteries Double Run Time
Echo, for instance, says its 58-volt CCS-58V4AH ($299) chain saw makes up to 112 cuts on a single full charge when you cut 6-inch logs. That’s the longest run-time claim that we saw for any battery-powered chain saw. However, we found that the number of cuts that you get depends on how sharp that your chain is and whether the log is a hardwood, such as maple or oak, or a softwood, such as pine or spruce.
Packing in the Teeth
We made roughly 20 cuts on 6-to-8-inch logs with the brushless-motor models that we evaluated, and all of the models still had full charges on their battery-charge indicators when we finished. That’s a significant improvement over the results of our previous evaluations of low-voltage battery-powered chain saws, which lost their charge quickly.
Manufacturers tell us that leafblowers that have brushless motors have a longer run time than do conventional battery-powered models. However, we found that almost all battery-powered leafblowers last at least 30 minutes on a full charge, and 30 minutes is more than enough time to clear short paths.
If you have to have a chain saw that cuts nonstop for hours at a time (say, for processing firewood) or a leafblower that clears large areas, you still should get a gasoline-powered model instead of a battery-powered model. However, if you want to do clean-up work around the yard without worrying about fuel problems or a cumbersome extension cord, we believe that it’s difficult to beat the convenience, light weight and power of the latest battery-powered models.
Patrick White has covered landscape topics for 20 years. He’s written for Turf Magazine and Tree Services Magazine.