Good News from El Salvador Dear Home Power, We just finished our second successful PV installation in El Salvador. Things have been going really well. We installed the first system in a community of 250 people called El Sitio. It's an amazing place. About ten community members helped install the system and three of them are in charge of the maintenance. It's a one panel, two light system for the building which acts as their community center, school, and health clinic. They now have adult literacy night classes. People who have always wanted to learn how to read but always had to work during the day, now have their chance. In fact, people from neighboring communities all around El Sitio are going there to study at night. The only problem is all the children want to be in the class as well, and class is disrupted with all of the kids hanging around. So now the community is hoping to put in another system so that the children can have their night classes as well. We installed the second system in Nueva Esperanza, a repatriated refugee community of about 200 people. It's another amazingly well organized community. Since their community center is larger, the installation consists of 2 panels, 4 DC lights and a 150 Amp-hour nickel iron battery. They're excited that they can now have meetings at night instead of taking time out of the work day, and are looking for a teacher who can teach literacy classes at night. We are also teaching nine women in Nueva Esperanza how to build and use solar ovens. The workshops are going incredibly well and the women are all very excited to start using their ovens. We cook in ours almost every day, and last week when the beans came out perfect, everyone became a solar oven convert. I think beans were the true test. It's really exciting working in El Salvador. The enthusiasm for solar energy is incredible. It is also so satisfying to see people putting the energy to such important uses such as literacy classes. Thanks so much for all your help with our project. The project could not have happened without help from people like the Home Power Crew and the Solar Technology Institute. I hope your Columbian trip went well. I'm looking forward to the next issue, if it makes it this far south, Laurie Stone, Nueva Esperanza, El Salvador When Laurie, Julie, & Ben left for El Salvador, the news was that Nueva Esperanza and the surrounding area was totally washed away by a major flood. These dedicated folks decided to go anyway, so this letter was cause for celebration. For more information on what Laurie and friends are up to, see HP#31 page 28. Here is a very worthy cause where all donations go to the cause, instead of some fat cat's bank account. If you'd like to help, donations can be sent to Solar Community Projects, c/o Laurie Stone, 5060 Overlook Rd NW, Washington, DC 20016. Ä Karen Perez A Unique Opportunity for Solar Energy Education Industrial designer and solar boat builder Hartmut Ginnow- Merkert will donate his $12,000 "Neah Bay" (Home Power #26), winner of the first solar boat regatta in the US, as a solar energy educational "vehicle". He particularly welcomes inquiries from high schools, but any other educational use would be just fine. The "Neah Bay" is fully operational and ready to run. "I built the boat to learn about solar energy and solar boats", says Hartmut Ginnow-Merkert. "It fulfilled its purpose for me, but many students could learn how well clean sun power propels a boat without noise and pollution. You have to see and feel it!" Hartmut will move back to his native Germany in April, to teach Design in the city of Berlin. He is already planning his next generation of solar powered river boats, but wishes his American solar boat efforts to make a lasting difference. The "Neah Bay" presents a unique opportunity for any high school to get involved in the growing number of solar energy activities nationwide. The boat encourages hands-on experience in a team setting. Please request application kit from Hartmut Ginnow-Merkert, 1840 Lakeview Terrace, Orono, MN 55356, 612-473-8699, FAX 612-476-6135 Iowa RE Fair The first I-RENEW Energy Fair, October 17, 1992, held in Cedar Rapids, Iowa was one of the most exhilarating experiences one could ever imagine, but the amount of work involved could never have been imagined! Tom Deves, Jim Sievers, and I originally thought last May that an energy fair in Iowa was maybe possible next year (1993). That was our experience! We decided to try the fair idea, with no real idea what was involved. We decided on Cedar Rapids mainly because it was close and, originally, because we were to be the Eastern Iowa Fair. With a visit to the Cedar Rapids Convention and Visitors Bureau, we realized the idea had a few believers outside our group. The bureau donated a telephone line to make contacts. One full day day of telephone calls and many miles of walking resulted in $50.00 from one bank. YUK! The bureau did donate 500 brochures and a computer to design our flyer. Tom Deves returned from the Midwest Renewable Energy Fair in Wisconsin in late June with the announcement that Home Power had an ad in their August/September issue. I-RENEW greatly appreciates this; we received calls from people around Iowa and surrounding states. These calls convinced us this fair was not to be just a local affair. In late August, Tom Deves and I attended a four day conference near Des Moines sponsored by the Union of Concerned Scientists. The workshop we found most beneficial was on using the media for advertising our fair. The UCS mailed an article about our fair to all its members. My wife even received a call from Denmark. One of the simplest things learned about media was: just ask. We received advertising from radio and TV stations in Dubuque and Cedar Rapids and the Cedar Rapids Gazette even printed an Opinion/Editorial article about our fair. We just asked! Originally, I thought this would be a nice little local event. What we ended up with was 30 displays and booths as well as Iowa University's solar powered car and an electric/PV truck. The 5 workshop tents were busy most of the day with 24 workshops on active solar, PV well pumping by A. Y. McDonald, Chad Lampkin's shops on photovoltaics, methane by Al Rutan, the methane man, and Mick Sagrillo on wind, to name a few. Chad Lampkin was very generous in setting up a 1000 watt system (with 40 donated Exide batteries). We had a 17.5 kW wind charger on site that could have been used if needed. Things I personally learned from this experience: The amount of time required to put on an energy fair is unbelievable. Do not spread yourself too thin. I, personally would turn the tent raising, video taping, announcing during the day to others. Do the things that are enjoyable to you. I would make the telephone calls, write newspaper articles, have a booth, and do workshops. The above description of how to organize a fair is a brief description of the time and events required. There are not enough words, space, or time to do justice to this project. Also, to the many people who had displays, workshops, or just helped, again thanks to all. We will see you all again next October (1993), Tom Snyder, 611 2nd St SE, Dyersville, IA 52040 Thanks Tom! As you can see if you check out Happenings in this issue, Energy Fairs are cropping up all over. Input from folks who have done it is invaluable for folks who want to have a Fair in their area. Ä Karen Perez There's always room for more fairs! If you are planning one in your area, let us know so we can spread the word! Ä Therese News from Down Under Dear Richard & Crew! A friend gave me a copy of your magazine (issue #24) a few days ago. I'm now trying to get your magazine from the local news agency/book store. We don't have magazines quite like yours in Australia. I have been dreaming about living off the grid for years, but I have very little knowledge of electronics & electricity. What little money that we have is used for becoming debt-free and to feed my kids. The point is that I will have to Homebrew and scrounge the batteries, generators (alternators) etc. Are there any batteries that could be homemade by persons with above average mechanical ability? I'm interested in alternative sources of energy, home power, self reliance, permaculture, home shop machining (A'la Gingery and The Home Shop Machinist) home wine brewing, local self- reliance & related subjects. Would like to correspond with people with the above interests. Yours Sincerely, Bill Beke, P O Box 9, King Lake 3763, Victoria, Australia Ain't it Grand! From little seeds big wonders grow. So sharpen those pencil, click those Bics, and exchange those itty bitty seeds. Ä Karen. You could make your own batteries by stacking layers of lead in sulfuric acid, or nickel and iron in sodium hydroxide. But the materials are toxic, yet easily polluted by even the minerals in household water. Instead, inquire at telephone companies, airports, etc for used batteries. As we continue to discover, though, there's no end to the renewable equipment which can be home-built. We were sent a copy of "Soft Technology" published by Alternative Technology Assoc., Inc., 247 Flinders Lane, Melbourne, VIC 3000, Australia ù 03- 650-7883. Looks like a great magazine, Australia's version of "Home Power". Ä Chris You're Late HELP! December first has come and gone. And I've no idea what went wrong. I've checked the label, I've checked the date, and in dismay I have to say, you're Late! Expectantly, Pete Ivanashchenko, Round Lake Beach, IL December was a brutal time, Everything was not so fine. The trip down South ran us round ' n round, Then our printer let us down. We're sorry that we scared you ever, But we figure, better later than NEVER! Ä Karen & The Wiz Keeping Cold in Canada I have an off-grid PV powered cabin which is used about 2 months per year, which we hope will become our full time home in the near future. (6 Solarex MSX-60 PV panels, SCI 30 controller, Trace 2012 inverter, 1500 Amp-hrs of C & D lead- calcium cells. I would anticipate added cells and possibly a wind generator should we move in full-time). We use propane for cooking, water heating and refrigeration, inverted PV for water pumping, lighting etc. Propane refrigerators are now illegal in Ontario for indoor use because of carbon monoxide poisoning incidents and I hope to move to electric refrigeration. However, the $3000 (Canadian dollars) cost of a larger Sun Frost is not all that attractive (though I recognize it would be cheaper in regular use than the cells I would need to power a conventional fridge). Which leads me to my request Ä I would love to see articles on "build your own" high-efficiency fridges. For example, has anyone taken a conventional fridge and retrofitted an efficient compressor like a Danfoss and added insulation? How about a through the wall design that takes advantage of winter but has enough insulation to avoid freezing food in a northern climate and has an added insulation panel for summer? What about cold cellar designs that take advantage of ground temperatures and vent heat outdoors in summer, and into the living space in winter? My problem in implementing any of these ideas is figuring out the proper sizing of compressors, box, and insulation for differing ambient temperatures. Are there any plain English design manuals for refrigeration DIY'ers? Thanks, David Poch, 376 Montrose Ave, Toronto, Ontario M6G 3H1 A fellow Canadian, Bob McCormick of Northern Alternate Power Systems describes his homebuilt 12 Volt DC refrigerator in HP #16 using a Danfoss compressor. Also, in HP #21, James Davenport describes his homebrew 'fridge. The Cooks' in Pennsylvania (cover of HP#29) built their own refrigerator/freezer. I have heard about through the wall designs to take advantage of the cold of winter, but haven't seen designs. Sounds like a good idea! Any plans out there, readers? Ä Therese Clean Water Dear Home Power, The project for Colombia's Paez Indians (HP #32) is wonderful. Thank you! The question that came to me reading about it was: what about the ongoing water needs of the battery pack? If this remote community cannot get their shipment of throw-away plastic bottles of distilled water from the city, won't they be tempted to use the local product? By doing this won't they damage the batteries in the long run? As an owner of nickel-iron batteries I know of their voracious appetite for distilled water. Why not build and supply such remote systems such as these (as well as the systems we are living with) a solar water distiller? Is there a reader out there with a good design we can all make? Could it be as simple as a flat plate hot water panel with a medium which water can be slowly trickled over in place of the fin and tube absorber. As it heats and evaporates it condenses on the slanted glass cover and then rolls down the glass as pure distilled water to be captured at the bottom? Sincerely, Rob Harlan, 42451 Road 409, Mendocino, CA 95460 Hello, Rob. Laurie Stone and friends took solar water distillers to El Salvador. These mini distillers are designed and made by McCracken Solar, 329 W. Carlos St., Alturas, CA 96101. In the case of Mosoco, Bijou is planning regular visits to check the batteries. Ä RP Hi HP Crew, Thought I would pull up a typewriter and wish all of you the best for the holidays. Received issue #32 of Home Power this past week. Good solid issue. I skipped through reading what appealed to me the most. Then went back to fill in the blanks. Finally read everything from front to back. Richard, I enjoyed your article on bringing solar energy to Colombia. Both you and Karen are to be commended for your action. I hope this seed planted will grow and flourish. I hope the undeveloped countries can skip the excesses we went through in becoming an industrialized nation. Therese, I enjoyed your article, "Me and my panel." I have a lot of empathy with you as I too try to design a system. And make it grow. I work on a tight budget, so I order one piece of equipment a month. Mail order. Best price I can find. I have a Hoxan 4810 module, a Trace C30A controller, and a 12 Volt DC load center (12 fused circuits). Next month I'll order a 2 pole- fused disconnect switch. Then two 6 Volt Trojan batteries. Plus the wiring and such that go with the system. But you have one up on me, Therese. You can check the electronic wizards on the staff. You can look at systems already set up. And you can order from a dealer locally. It's a bit different in Texas. No dealers. No systems to see and examine. I operate in a vacuum. Call myself a solar sponge. A very dry one. I can always learn something new, when I read about renewable energy. The only modules I have seen are the ones I have ordered through the mail. The only systems are the ones I plan and dream about. I learn from books, catalogs, and magazines. Especially Home Power. I have a stack of the "bible", all the issues from start that were available. I find myself going back and looking for subjects. "Things that Work!." Pieces on soldering. Wiring several panels together. Charging small nicads. Don't get me wrong. I'm not complaining. I'm having a great time using renewable sources of energy as a hobby. And believe me, old dogs can learn new tricks. I bought a PowerStar 200 plug-in inverter from Electron Connection. And learned that an inverter uses a lot more power doing its thing. Inverting. I was wondering how many amps a unit would draw after going through the inverter. But never did find out, for the inverter was drawing 20 Amps just switching from DC to ac. So I learn by trial and error. Have a Black & Decker electric lawn mower. Thought I might be able to power it from my portable unit (see HP #). Mower has 6.5 amps stamped on label. Hard to read. If 6.5 amps x 110 volts = 715 watts, there is no way my plug-in will work. But I plugged it in and the mower ran. Took a short time to rev up. And it did not have full power. But inverter stayed on. Although the lawnmowing operation does not work, the inverter does help run some tools in my workshed. The 3/8 drills runs fine. And I hope to see if it will work on the new system. Read somewhere that small plug-in inverters will not work on grounded house systems. Guess I'll find out. I recently bought a string of LED Christmas lights from Backwoods Solar. I hung these under a bookshelf in the middle of my trailer. Plugged it onto a 5 watt Solarex module for daytime use. At night, switch it to an Innova 12 Volt DC power pack. Works fine. Well, I'll get off the line. Have enclosed two clips form the Dallas Morning News. One about "green" refrigerators. Wonder why they did not just use Sun Frost. Other clip is on a digital phone setup in Texas. Wishing all the staff an Enlightened Christmas. And a real high powered New Year, N. Bleecker Green, POB 304, Royse City, TX 75189-0304 Hi. Glad you enjoyed the article. Part of the inspiration for my system was seeing your system in HP#31! I think anyone can set up a small system; it just takes some time and patience (especially for beginners). I'm a bit spoiled here at Home Power. You can learn a lot with great teachers and I sure have quite a few electronics wizards around here to help me with my system. We try to teach through the magazine, at all levels from beginners like me to homebrewers. But we couldn't do it without input from readers, sharing your systems, whether simple or complex. We can sure learn a lot from each other! Thanks Ä Therese. Hello N. Your POW200 drew 20 Amps when you had no ac loads plugged into it!? Mine uses 0.25 Amp (3 watts). I'd check your measurement again, but it sounds like it's working if you managed to run your lawnmower with it! A 1991 or newer model POW200 will give as much current as it can to a load. If the load is much greater than 200 Watts (as your lawnmower was) then full power won't be delivered. The POW200 is better suited for loads 200 Watts and under, like your drill. Under no circumstance plug your inverter into your house's utility-supplied power. But there should be no problem powering small ac loads, whether or not they're grounded. Ä Chris Dangerous Diodes People, Your low ac voltage detector circuit printed in Home Power issue #32 contains a hidden fire/safety hazard. My concern is with the inverse voltage rating of the 1N4003 diodes in the voltage-measuring bridge. At a line voltage of 117, the rms voltage across the bridge will be 100. In a perfect world, the peak voltage would be 142. The filter capacitor would charge to slightly less than this, so the peak inverse voltage across the bridge would be just under 284. The 1N4003's inverse voltage rating is 200 and there are 2 of them in series. Theoretically, this is OK Ä barely. As all of us know, real power lines have large spikes and surges, and real diodes in series may not share the inverse voltage equally. The PIV of the 1N4003s will often be exceeded. Sooner or later, one of them will short. When that happens, the 10K input resistor will be connected across the line (through a surviving 1N4003) on alternate half cycles. The rms current through it will be 11.7 mA and the dissipated power will be 1.4 W during those half cycles. The average power is only half that, of course. A typical, unwarned, builder of the detector will probably use a quarter watt resistor mounted on a circuit board. When it is asked to cope with 0.7 watts, something unpleasant will happen. Usually, it will only be smoke and frustration, but we can all think of worse possibilities! You may think I'm being over-cautious, that 1N4003s will take it. I've had embarrassing failures in a more conservative design. In equipment I build for a living I used 1N4002s (PIV 100V) in a bridge across the 24V secondary of a transformer. Two out of about 15 units failed within a year. I lucked out Ä the transformers had internal fuses and no serious harm was done. Since then, I have used 1N4005s (more PIV than necessary, but cheap) and added an external fuse. I've had no more problems. I have two additional, less-important suggestions about your article. I believe any equipment connected to the power line and left in operation unattended should be fused. Also, I suggest that you warn users to be aware of the load controlled by the output relay in your circuit. It is easy to overload a 10A relay with several fridges, freezers, etc. It will operate OK for a while, but may overheat dangerously a few months or years later. I like your idea of using a 723 as a combined comparator and voltage reference. Neat trick! I'll probably use it in the future. Good luck, and keep up your brewing, Dave Cochran, SE 605 D McKenzie st., Pullman, WA 99163 Our apologies. My only comment is that in our experience, diodes blow open circuit, so the resistor wouldn't have a chance to get hot. But as it stands the diode bridge is a serious design flaw. We should have used 1N4005s, with a 600 V PIV. We also should have used a fuse. Ä Chris G & Amanda P Hydro Help This letter is due to the surprised reactions I encountered at SEER 92 when I mentioned the fully automatic hydro system installed by my friend Bill Walton at his home near Cazadero, CA. What appeared to him to be simple and logical is apparently not so obvious to everyone. Bill had developed a spring high on a hillside and wanted to put in a hydro system, but was concerned about running low on water because it was also used for fire control. His solution was to automatically shut off the flow to the Harris wheel when the batteries reached full charge, thereby not only conserving water, but also saving wear and tear on the wheel and reducing noise as well. This was accomplished after the folks at Harmony Farm Supply provided a sprinkler valve equipped with a 12 Volt DC solenoid (about $45 for the one inch size) and Real Goods supplied a Trace C30 (not C30A) voltage controlled switch to control it. When the C30 calls for charging, it supplies 0.54 Amps to the the solenoid which opens the valve and the wheel starts spinning. At full charge the C30 drops the solenoid, the valve closes, and the wheel stops. Note that since the wheel stops, there is no load diversion necessary and therefore no high current switching! There is no problem with the water hammer since the valves are built to control a high flow and do not slam closed and also they are only seeing about a 20 pound change between static and dynamic pressures. The power house is a small shed and supplies ac to Bill's home from a Heart inverter. Bill Walton receives his mail at 30862 Bohan-Dillon Rd., Cazadero, CA 95421. Although Harmony Farm Supply is listed as being in Sebastopol, their mail goes to P O Box 460, Graton, CA 95444 and their telephone is 707-823-9125. Sincerely Yours, Don Nielsen, P O Box 627, Bodega Bay, CA 94923 Thanks for the letter, Don. Great regulation scheme! Bill's hydro system is a great application for my Homebrew this issue. If you like homebrewing, consider substituting the Trace C-30 load controller with our simple circuit. The homebrew circuit will be much less expensive and fun to build.ÄAmanda Dueling System Dear Home Power; I am currently working on a solar electric design for my grid-connected suburban home. Although I plan to handle most of our loads using an inverter and the current wiring, I do want to run a couple of significant loads on DC (Sun Frost fridge/freezer, pumps for constructed wetlands and irrigation, some key area lighting, ceiling fans, etc). Because of the loads and wiring necessary, it is very desirable to use a 24V system. However, There ARE still things that want 12V - car stereo, small electronics, etc.- I have seen nothing in my searches dealing with dual voltage systems, save the Vanner charge equalizer. As far as I can tell, this device works by "wasting" energy from the top "half" of the system equal to that drawn from the bottom half. Of course there are always voltage regulators which are another lossy way to power small loads only. Are you folks aware of other ways to do a dual voltage 12/24V system? Thanks for your time and a great magazine, Stephen Pope, POB 1045, Los Alamos, NM 87544 Hello Stephan. The Vanner is probably what you want; see the Things that Work! review on page 84. It's not a linear regulator: it doesn't "waste" half the voltage. It transfers current from the one 12 Volt string to the other in a 24 Volt pack. It does this with over 90% efficiency using high frequency switch mode power electronics. Ä Chris Wind Heat Dear HPM; Since we have recently bought a new abode here in the Red River Valley (Fargo-Moorhead area) we hope to equip part of our small farm with renewable energies. As you can imagine, wind in this part of the world is in abundance. We hope soon to buy a wind generator for the property for the initial purpose of heating a small (1- 2' X 16') greenhouse by hot water heat. (Rural electrical co-op price here is 8.5 cents/kwh.) Have you run into anyone doing this, or have any suggestions for what type of systems (heaters, piping, electrical interfaces/inverters) would be recommended or required? We're trying to stay at the I kilowatt level or less with this implementation. Although direct solar power is lacking a bit here relative to the southwest, enough sun shines to interest us in the use of small fans placed through out the house for air circulation in both winter and summer. Any leads on who sells a good variety of fans for such a purpose? Finally Ä on a more Rube Goldberg note: Many electric golf carts are adorned by a small canopy providing shade for the driver. Would replacing the canopy with a solar panel (3' x 5') generate enough juice to recharge the battery (after, say, 1/2 discharging) within a day in the northern midwest? Thank you for any help you can provide on these questions. Sincerely, John J. Weiland, RR #1, Box 44, Sabin, MN 56580 Hi John, On one hand, heating a green house with electric heat produced by a wind turbine has some advantages: when it's cold and windy, the heater will produce more heat; and the control electronics would be fairly simple. On the other hand, you'll need a pretty large wind turbine. I imagine it will take at least a couple of kilowatts of electricity to heat a greenhouse that size, and that's a big, expensive wind machine. Insulating the greenhouse for the cold season, and using some sort of night time blankets over the windows would be money well spent if you plan to make your own electricity to heat it. I wouldn't use an inverter Ä electric heaters don't care whether the current is DC or ac. Lots of folks sell small electric fans. Try Backwoods Solar Electric, AEE, etc. On powering electric golf carts with roof mounted solar panels: it sure would be an excellent promotion for PVs, exposing America's golf-playing executives to solar power. But you couldn't expect it to recharge the cart in a day. I could see fitting four 50 watt panels on top of a golf cart. Golf cart battery packs are 220 Amphours @ 36 Volts. Half discharge, then, is 3960 Watthours. It will take the 200 watt canopy array at least 20 hours in full sun to recharge a half-discharged pack.Ä Chris Opportunity Knocks Richard, Karen and the HP Crew: Headlines and TV-news clips I wished I'd seen in the aftermath of Hurricanes Andrew and Iniki: "Temporary power quickly restored for thousands by portable solar electric systems." "Their emergency generator doesn't need gasoline!" "Emergency solar-powered lighting helps prevent looting" There is a real opportunity for our industry if someone will produce such a unit. It could be as simple as a camping-type ice chest, 2 sealed batteries, an unbreakable module on top and a small inverter -- transportable by two people (under 150 lbs.) Mass production and distribution to major relief agencies such as the military and Red Cross would show millions it really works. Toss in a 50 ft. extension cord to plug into an outlet with a waterproof cover and they're in business. Such units could also appeal to the survivalist/camping/on- grid folks in these days of increasing grid outages. While we missed the boat this time, perhaps someone can prepare for the next major disaster, and show what really works. A real publicity opportunity. I'm reminded of the 1987 forest fires here in California, when the beer giant, Anheuser-Busch, shut down their West Coast facility to produce millions of re-labeled beer six-packs filled with drinking water, which they distributed to fire camps free of charge. Today they're collectors' items. No advertising could buy that publicity. Maybe our industry can do something with similar impact to help in the next disaster. For broader public relations; Chuck Heath, Suntricity, POB 1159, Coulterville, CA 95311 ù 209-962-7012 ù 209-878-3557 Hiya Chuck, good to hear from you again. Phil Jergenson of SunTools (707-459-2453) has developed a small PV/Gel Cell/Inverter ice chest like you describe. I'm surprised that you didn't see it at SEER'92. It should work fine for radio communications, TV reception, or a couple of lights, but to power anything serious-like refrigeration, the thing most needed in Florida-we quickly get into space/weight problems that limit portability. The Voltar (HP28,pg30) portable power system which can fit into the back of a pick-up would be the hot ticket. It has enough power to run a medium-sized camp or emergency kitchen. Combined with a power priority management system such as the Cruising Equipment "Backofftm", it could provide limited power to a small subdivision. The problems are strictly financial. On the industry side, I don't know of many companies who have the bucks to put a number of these things together and sit on them just waiting for an opportunity to show off our stuff. IBM we ain't! On the government side, FEMA and related agencies are looking at pretty short-term goals. In their view, a generator costs X amount and that's it. Never mind the associated fuel and maintenance costs after the purchase, that's the recipients responsibility. Environmental concerns don't even enter into the equation. You can agree or disagree with arguments about the cost-effective use of limited funds, but that's the way it is. The good news is that there may be hope. I've been working with some folks in the Round Mountain, CA area (the scene of a devastating wildfire this past summer) who have convinced a FEMA representative to try some very small scale solar powered water purification installations. If it all works out, you can bet you'll read about it in HP. - Bob-O Solar Grass Cutter In Home Power #30, the letter in Q&A asked about battery powered lawn mowers; I have built two prototypes that work fairly well. The first one had a 5W solar panel mounted on the handle and was powered by two Sears "Die Hard" motor cycle batteries. It ran most of last summer (1991) without a recharge from from my battery charger. It was slow at grass cutting due to low blade RPM. The second prototype has three 12 volt, 7 AH, sealed batteries and works really well (high RPM). It will run between one and two hours before it is totally discharged. The neat part about mower #2 is; I'm experimenting with a roof mounted solar array to recharge it. I don't have all the bugs worked out yet because of the recharge time and grass growing time, but it looks promising never the less. I suspect we will be using many more solar/battery mowers in the near future. I'd be manufacturing them today if the right people here in Phoenix would take an interest. As yet no one is ready to help. Most any backyard mechanic can convert a gas mower to solar. I'm surprised there are so few in operation. They are quiet, pollution free, and easy to mow with. Sincerely, Larry Malinak, The Arizona Solar Energy Association, Box 26, Scottsdale, AZ 85252 Well, Larry, 1,000 more electric lawn mowers are in operation due to a research project by the Environmental Protection Agency. The federal government is letting 1,000 people swap your gas guzzling pollution spewing lawn mower for a cordless electric model to develop better ways to cut pollution caused by the gas mowers. The EPA and the National Consortium for Emissions Reductions in Lawn Care made its offer through nine participating utilities. The EPA tests the gas mowers for emissions. The Consortium monitors the electric mowers for performance. The consumer gets a free electric mower, for keeps. Unless, after a year, he wants his old one back. The EPA estimates that using a gas powered mower for one hour generates as many ozone creating pollutants as driving a car for 50 miles.- Kathleen More Mower Dear Home Power: Re: Noel Perrin's battery powered mower question in HP#30 and Martin Holladay's reply in HP#31. Black & Decker (800 762 6672) has a light duty 12V cordless mower, with optional catcher, which will mow up to 10,000 sq ft on a single charge. The price is $500. Aside from the previously mentioned Kansas Wind Power; we folk at EO custom build medium to heavy duty 12-36VDC push and self-propelled walk behind mowers. We also recondition the mentioned GE Elec- Tracs. These venerable ole machines were one of the best EVs ever made. It hasn't been manufactured since the '70s and I fail to see the relationship to nuclear weapons and the GE boycott. GE did the market place research; engineering; manufacturing; and the initial selling; before licensing the rights to manufacturing to several other companies. They were sold locally by Wheel Horse, New Idea, and John Deere. I've heard others had the rights also; but I've never personally seen them. All companies failed to properly promote them. They were treated as a novelty item. However, they are a serious contender for the IC toys available in their class; as well as being considerably more economical to own/operate. The Elec-Trac is a rugged high torque homestead tractor; which takes all of the disadvantages of a highway cruising EV and turns them to advantage. On top of this, they love solar juice! Several thousand were manufactured and most are still running or reconditionable; a tribute to their longevity. There is a market (at least in these parts) which seems to be growing for obvious reasons. I'd be willing to do an article on this DC beast of burden, if there is sufficient interest. You'll find "ET" owners "cultists" almost to extreme; and I'd be hard put to keep the article short. I'd also appreciate it; if anyone wants info on same to send along a couple of bucks for my time and a serious info return. Vertis Bream, Energy Options, 1755 Coon Rd., Aspers, PA 17304 By all means, we'd love an article on electric tractors! The benefit (instead of penalty) of weight, the high starting torque of some electric motors, and a tractor's tendency never to travel far from home all point towards battery power. Forget Fossil Fueled Farming! Ä Chris