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208Re: [hreg] Workshops and threads

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  • James Ferrill
    May 12, 2000
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      Chuck Wright wrote:

      > James Ferrill wrote:
      > > That's how my solar lawn equipment project got started. I needed to make better
      > choices, and invent them if necessary.
      > Nice to have this interaction going on! Tell us more about your
      > solar lawn equipment project...
      > Chuck Wright

      Hey Chuck,

      What I have observed is that although solar technology has advanced, no one other than a
      few interested people have actually made use of solar energy in a practical way. If I
      went to my neighbors and poured my guts out all day about why they should be doing more
      with solar, the conversations would always end up focused around 2 questions, "How much
      will it cost?" and "Where do I get the stuff?". This is where the equation always breaks
      down. How to answer the question, "How do you implement use of solar power for XXXXXXX
      in a suburban environment?".

      I've reasoned that I need to start by doing a small project that everyone can relate to
      and that would make a difference that mattered to my neighbors. The project I came up
      with is a solar recharged lawn mower. If you know how much pollution lawn equipment
      emits, it's a sickening feeling when you walk outside on a weekend and see all your
      neighbors mowing, edging, and leaf blowing with poorly maintained, dirty, polluting
      equipment in Houston (which is now the pollution capital of the US, it seems). What made
      it so important to me is that I know a number of people and friends that have asthma,
      including my wife. That kinda makes it personal because I'm using the same bad

      I knew that the only things I would have to buy are a standard cordless lawnmower, a
      charge controller, and solar panels. That's it. The mower can be something like the
      cordless Black and Decker CM1000, 5 hp, mulching mower which is in stock at any Home
      Depot. The other two items are also stock items that I can order online from any number
      of vendors. I'm going to put an hour meter on the mower so I can log how much time it
      has spent mowing. Maybe I'll paint it gaudy colors and stick on solar stickers to
      attract attention too :-)

      After I started working on this, I decided to expand the project so that my shed and
      everything in it or plugged into it would be solar powered. This way I would be able to
      power my weed eater and leaf blower as well as the lawnmower, run the shed interior and
      exterior lights, and have a demonstration system that people could come and see how
      solar is utilized. My old physics teacher lives in my neighborhood, and I envisioned
      being able to let him bring students over to see how solar can be used for real and not
      just read about it in a book.

      After the equipment is built and tested for a time, the project needs to go on the web.
      I want to start with a domain name like suburban-solar.org or .com and make it a base of
      information of my journey to put solar energy to use at my suburban home. Along with the
      main page, I want to have a page for each project. I can put all the information on this
      page that anyone could want, like specs, runtime, charge time, principles of operation,
      etc. And the best thing I want to put on there and update on a regular basis is the
      amount of time this mower has been running and a list of how much pollution has been
      eliminated in detail. I can get people to visit the web site to see what can be done. I
      think it would really make an impact on my neighbors to see and realize just how much
      NO2, CO, CO2, SO2, and VOC's that they and everyone else are spewing into the air and
      into their kids lungs. I can provide a link for people to email me so that I could
      answer any questions they might have. I had sent a similar letter to Greg about getting
      TXSES to host the web site and domain, and it didn't sound like a problem. I figured I
      would tackle this project in phases:

      1) Acquire the lawnmower and research it's internal circuitry to see how the charger can
      be alternately powered.
      2) Acquire and install an hour meter and connector for access to the internal battery.
      3) Build battery cabinet for the shed. I already had 4 golf cart batteries. Expand as
      4) Acquire the solar panels and install on the shed roof.
      5) Acquire a charge controller, 1500W inverter, and related hardware. Create a power
      distribution board to mount these components.
      6) Create circuit to recharge mower or simply run power cube off of inverter as needed.
      7) Create web site using documentation and notes kept as project has progressed.
      8) Spread the word.

      Phases 1 and 2 have been completed. I cut two holes in the lawnmower shell and mounted a
      small digital hour meter and connector to the internal battery. I have 2.4 hours of
      runtime on the mower so far. I talked with David Shaver in Canada, the man that actually
      designed the electronics in that mower for B&D and he gave me details on how it worked.
      Based on the strict current limited requirements of that small internal battery, I
      decided first to charge it normally using the original power cube running off the
      inverter and work on a direct DC-DC charger later.

      Phase 3 is 80% completed. I'm over-building the battery cabinet so that it's capacity
      can easily be expanded or the voltage changed from 12 to 24 volts. I've used 1.25" x 1"
      buss bar and 2/0 battery cables to minimize loss in the system. Two small fans in the
      bottom push any fumes or hydrogen produced during charging out a 2" PVC vent at the top
      to the outside. The box is 5' tall, 3.5' wide, and 2.5' deep, with two levels that can
      hold 8 golf cart batteries each for a total of 16 batteries max. Starting out with 4
      golf cart batteries will provide 220 Ah @ 24V or 440 Ah @ 12V. I'm designed enough
      headroom in there so that a larger, better battery can be used later, such as the Trojan
      L16's or equivalent. They're the same size, just taller than my current batteries.
      There's some serious framing in this cabinet since 16 batteries would weigh 1280 pounds.
      I can see my shed sinking into the ground already :-)

      I bought 2 Solec 90W panels and a Morningstar Sunlight series charge controller 3 weeks
      ago. After I finish the battery cabinet, they will be mounted on the shed roof (phase
      4). I've been taking pictures of each step as I build/add something new, and these will
      be scanned in later for the web site. If I get them scanned sooner, I'll email out some
      samples. That's where the project stands right now.

      James Ferrill
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