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Tuesday, May 26, 2015

My solar lawn mower - still going strong



Over eight years ago years ago I was inspired by a small article in Home Power magazine in which a guy named Al Latham described how he had converted his standard 22 inch gas powered lawnmower to use an electric motor and battery that he charges from solar.   I decided to make my own conversion and have been using it consistently to cut tall grass and weeds in our so-called lawn ever since.

At this time of year I transition from charging the mower from a standard automobile battery charger to using a couple of small solar panels on the south facing roof of my storage shed.  These panels combine to a total of 40 W which is enough to charge the mower in one day of clear sunlight.  The 10 amp automotive charger can charge it up in a few hours.
Gauges on the handlebar show battery Voltage and Amps drawn when the motor is running.  As you can see it draws up to 30 A and can sustain this for 20 minutes or so which gives me enough time to mow a large section of our quarter acre lawn.  

In the middle of the summer 20 minutes is about as much as I can handle because this mower is quite heavy with the very large motor and lead acid battery and it becomes sweaty work.   Nonetheless, it is a delightful mower to use because it is very quiet and powerful enough to cut through tall weeds.

Maintenance involves sharpening the blade every year and replacing the battery every 2 to 3 years at a cost of $60-$80.   So this is definitely more expensive to operate than a gasoline lawnmower, but it has zero emissions and may last significantly longer than one of its gas cousins.

If you want to learn more about the construction of my solar mower, I have a detailed blog on my website with clear instructions on how to build your own.