This weekend was the first time that I actually used my new cordless electric mower to cut my lawn. Prior to this I had tested the mower to ensure that it worked—in case I needed to return it since I bought it on mega discount at the end of last year’s outdoor season—and to make sure that the third party batteries I purchased online worked as well. Nothing would have been more disappointing then heading out to mow my lawn and hearing nothing.
My yard is just under half an acre, but not all of that is grass. A large portion is the house, driveway, sidewalk, etc. There are also quite a few trees and landscaping with more on the way this summer. I do not have an exact figure, but it is a large lot.
Most of the reviews of the cordless electric mowers that I have seen were conducted on small yards in places like Florida and California. These are the kind of yards that take twenty minutes on Sunday morning to mow. In the case of my yard it is more like 45 minutes to an hour depending upon mowing direction and how many foam darts I have to pick up.
To power the lawn mower I purchased two third party 6 amp hour batteries. These batteries were decently reviewed and I hoped that six amp hours would provide me enough extra capacity to mow my lawn without stoppage. Originally, the Ryobi lawn mower came with a single 40V 5 amp hour battery that I am going to use with a battery electric string trimmer.
Well, the first battery—from full charge until the mower stopped cold in its tracks—lasted just over thirty two minutes. This is a far cry from the forty five minutes I had read that a five or six amp hour a battery would last. However, I was using my mower’s self propelled feature so there is probably a decent hit to run time caused by the extra oomph it provided. Given how light the mower is the self propelled feature is more of a “nice to have” than a necessary evil. The next time I am going to forgo using that feature on the totality of my lawn to see the impact on battery life.
The second battery lasted until I completed my lawn approximately 20 minutes later with no fade in power. That is approximately 50 minutes of run time with one battery completely empty and another with electrons in the tank, so to speak. My plan is to keep track of the batteries’ performance across the season to see how operator error, weather, and cutting conditions impact performance.
Lawn mowers are pollution bad actors. The numbers are hard to pin down because there is so much variation—small engine, riding mower, CARB compliant, etc—but there is no doubt that an hour of mowing is worse than an hour of driving a car. It’s not just the carbon dioxide that is emitted by small engines that should concern you the most. These engines are veritable factories for compounds like carbon monoxide and nitrogen oxide. Nitrogen oxide, along with its friend sulfur dioxide, is the bad chemical compound that combines with atmospheric compounds to make acid rain.
For the season, I have eliminated ~50 minutes of gas-powered lawn mower operation with a solar powered battery electric lawn mower. Stay tuned for the ongoing accounting of how much I “decarbonized” my lawn care routine.