A report on the NALM Battery-Powered Mowing initiative

By Bobby Neal Winters
I have in this space before alluded to the fact that I have purchased a battery-powered lawnmower. It is a Ryobi 20-inch, 40-volt mower.  At the time I first told you about it, I was just getting started with it.  For the last 5 or 6 weeks, I’ve been mowing with it as part of a NALM-funded initiative to determine the efficacy of battery-powered lawn mowing.  (For the uninitiated, NALM is the National Association of Lawn Mowers.)
I was chosen for this initiative because NALM recognized in me a dedication to traditional lawn mowing as a practice.  NALM is dedicated to the personal mower, those mowers who wish to have a better lawn and to do it themselves rather than to hire professionals who can do it more regularly, effectively, aesthetically, and probably at a lower overall cost.  I have never hired a professional to mow my lawn: When forced to let someone else do it because of injury or travel, I’ve always hired a neighbor boy or a daughter’s boyfriend to do it.
I now mow my lawn in two parts: Front yard on one day a backyard on day two.  The front yard ordinarily takes about 30 minutes  and the backyard ordinarily takes 45.  The word ‘ordinarily’ is there to account for those occasions where ‘events’, usually rain, keep me from mowing on my spring schedule of once a week.  When that happens, the backyard can take an hour or more to mow.  This is germane to my report on my part of the initiative which follows.
My battery-powered Ryobi is lighter than my gas-powered mower.  This is because it’s frame is made of hard plastic.  It is plastic, but don’t think of the plastic your grandchild’s toy car is made out of.  This is more like a lighter bakelite;  it is rigid and not soft, but like I said, not as heavy as metal would be.
This brings up a point that will be an issue for many of you. When I got my Ryobi and discovered that you start it with the touch of a single button, I was thrilled. As you know, there are those days when you have to jerk multiple times on a mower with an ICE (internal combustion engine) to get it started.  For those who are getting older or of a smaller frame, this can be an issue.  The touch of a button to start the mower removes that problem with...uh...the touch of a button.  
I had hopes that my wife and mother-in-law would make use of the new mower because of this feature.  Sadly, that was not to be.  The plastic construction has put it into the category of one of my new toys, and they are terrified to touch it.  A  likely story.
I don’t know much about the specs on the motor.  One might be tempted to say that it is of a new, modern design, but I don’t believe that is necessarily the case. The bottleneck to increased use of electric motors in such application has been the relative low energy density of batteries to that of gasoline.  While there are electric motors and electric motors,  it is the higher energy density of lithium batteries that is enabling the increase in battery-powered mowers--and cars for that matter.
I paid $300 for my Ryobi.  It came with one 6ah battery. (The ‘ah’ stands for amp-hour.) Such a battery you can run at one amp for six hours or six amps for 1 hour.  It will run my mower for about 45 minutes, so the motor as I use it is drawing about eight amps.  For comparison, your washing machine draws 10 amps.  I wasn’t content with having just one battery, so I bought a spare 6ah battery for about $150.  From this, information we can derive the following. The electric motor is the cheap part of the mower.  Ryobi is not going to make it money from the mowers, but from the batteries. (The Japanese have learned a lot from us, haven’t they?) 
I have only had to use my second battery two times.  The first time I mowed the backyard, it was very tall.  It was so tall I had to readjust so as to not mow so close. (This is a very easy thing to do with the Ryobi, by the way.)  Nevertheless, the grass was so thick and tall it sucked one battery dry.  There was one other time I was forced to do the same thing because there had been an extended period between mowings because of the rain.  Neither of the two times did I use the second battery for more than 15 minutes. Lesson: I could have used a 5ah battery for my second battery.  They are much, much less expensive.
Because the mower is lighter, I am not as fatigued after mowing. Because it’s not run by an ICE, it is quieter.  It is not perfectly quiet, but it makes the noise of a very loud electric fan whose blades are hitting grass.
There is no oil to change.  This isn’t really a big thing to me. I’ve never changed oil in a mower: I’ve only added more.  But this is over in any case.  Because there is no oil or gas or any fluid of any kind, you can fold it up and store it vertically.  You’ve just got back 4 square feet of floor space in your potting shed.
For now it is working out well, I will share more as time progresses.
Bobby Winters, a native of Harden City, Oklahoma, blogs at redneckmath.blogspot.com and okieinexile.blogspot.com. He invites you to “like” the National Association of Lawn Mowers on Facebook. )