Mini Hybrid Power System R.T. Gaydos and Linda L. Gaydos © 1989 by R.T. & L.L. Gaydos Eight years ago we purchased remote acreage in the Sierra Foothills of Northern California and wished to build a small energy efficient cabin on it. After discussion with the local power company we were told that it would cost $10,000.00 to extend electrical service. Our cabin site is 1,800 feet from the closest power pole, and they charge about $5.60 a foot. Also, the power company could not even give us a possible date as to when we could expect electrical hookup. The only affordable solution was to make our own electricity by alternative means. We were fortunate to live in an area where there were two renewable energy stores, so ideas and advice were readily accessible. Hydroelectric In our area annual rainfall is 55 inches a year and runoff from Sierra Mountain snow melt creates an abundance of natural spring water. Our springs are well above our cabin site, so we've got gravity flow water. This coupled with the fact that a small inexpensive 12 Volt hydro electric generator was being made locally made the decision to go hydro easy. The main component in our system is the HydroCharger IȘ, designed and built by Sam Vanderhoof of Independent Power Co. in North San Juan, CA. This is the smallest hydro unit I know of. It weighs approximately 20 pounds and is 12" x 8" in size. The hydro unit has a 4" diameter pelton wheel rotating on the horizontal axis, connected to a small permanent magnet generator. According to the manufacturer, it will generate up to 2 Amperes of current and begins producing electricity with water flows of 12 gallons/minute at 3 feet of fall. We have about 40 foot fall with 500 feet of run, going from water source (springs) to cabin where the generator is located. The two springs we have tapped give us a total of 6 to 12 gallons/minute of flow depending on the time of year. This gives us from 1 to 1.5 Amperes from the Hydro. The hydro runs constantly, therefore we get 24-36 Ampere-hours per day. In our system water is collected in a catch basin under each spring, from where it runs into a 35 gallon plastic reservoir and through 1 1/4" PVC pipe downhill 500 feet to the cabin. Larger pipe, at least 1 1/2", should have been used to reduce interior line resistance. The hydro unit is located under the floor of the cabin with a valve running up through the floor of the bathroom, allowing the hydro to be turned on and off inside. This is helpful because our gravity flow water system that feeds the hydro unit is also our domestic water supply. When we are getting low flows of water, like late summer & fall, water pressure for showers is affected by hydro use. Therefore, we can turn off the hydro unit to obtain more water pressure for showers. Occasionally cleaning the debris from the catch basins' screens is the only maintenance needed for the water collection system. The only maintenance adjustment we need to make on the hydro unit is to change the water nozzle size, depending on available water, ie. too big of a nozzle without enough water will cause air to be sucked into the water line (penstock). Nozzle orifice sizes we use are 1/4" to 1/2" in diameter. We originally had trouble with the HydroCharger IȘ and replaced the lower bearings in the generator unit several times. Acidic water was getting inside the generator and causing severe corrision. This problem was solved by the manufacturer, by elevating the generator from the housing with 3/4" stand offs and putting a splash guard collar on the generator shaft. This modification is now standard. Since last bearing replacement and modification, the HydroCharger IȘ has run continuously for 4 years without any trouble. It is a very reliable component. Photovoltaic Another part of our mini hybrid power system is a single Solex 35 Watt PV panel, it produces 6 to 10 Ampere- hours per day. The panel is located on the roof of the cabin and is accessible by a roof ladder for cleaning, snow removal and redirecting toward the sun. Although roof mounting is not best, it was the only place close to the cabin that would give optimum solar exposure. The PV panel was also purchased to qualify the system for the now defunct State & Federal Solar Energy Tax Credit. Back up Power The third producer of this hybrid system is a used 2,800 Watt Yamaha gasoline engine/generator. It is used in conjunction with a Sears 50 Amp heavy duty battery charger to charge the 12 Volt battery bank when it gets too low. It is needed infrequently to charge batteries, but is necessary to run a 10" radial arm saw and Maytag clothes washer. Energy Storage - Battery Bank The 12 Volt power produced by hydro, solar panel or generator/charger is transferred and stored in a bank of deep cycle, lead-acid golf cart batteries. There are six, 6 Volt, 220 Ampere-hour batteries wired in parallel and series to yield 660 amps, 12 Volt storage bank. Batteries are located inside the cabin in a window seat/battery box. The box is sealed to the interior of the cabin and vented through the wall to the outside. The vent dissipates the hydrogen gas created by the batteries. We have used the same collection of batteries for four years. Unfortunately, all six batteries were not purchased at the same time, i.e., the first set was used, the second set was purchased 9 months before the third set. This was definitely an error because batteries develop a charging memory and will only accept a charge as high as the oldest or worst battery. None the less, they are forgiving because the batteries are continuously being charged by the hydro unit. If we were depending primarily on solar panels, we doubt that the batteries would be so forgiving. See HP9, page 27, for more info on lead-acid batteries. Distribution and Consumption of Power From the battery bank, 12 Volt power goes through a DC circuit breaker panel and to its various points of consumption. We have eight separate 12 Volt circuits. 12 Volt battery power also supplies the Trace 1512 inverter. The inverter's ac power then goes through an ac circuit breaker panel and on to various points of ac consumption. There are four separate ac circuits, with one going up to the woodworking shop which is 100 feet away from the inverter. Appliances run by 120 vac inverted power are a small microwave, phonograph turntable, word processor, toaster, blender, mini drip coffee maker, vacuum cleaner, hair dryer, hair rollers, small clothes iron, 8" table saw, 7 1/2" skill saw, drills, sanders, 10" miter saw, etc. The only thing the inverter will not run is a Sears 10" radial arm saw and an automatic clothes washer. These must be run by the ac gas generator. All ac appliances were purchased with energy efficiency and low power consumption in mind. The main consumption of power in our system is lighting by 12 Volt. We have 14 separate lights, which are either incandescent, fluorescent, or quartz. Fluorescents seem to be the most efficient (illumination/amps) with quartz a very close second and incandescents a distant third. We have strategically placed lights and semi-gloss white walls to help reflect light. Location is the most important factor in efficient lighting. Lighting uses approximately 1/2 of the power we make. The remaining 12 Volt appliances, 12" B/W TV, Hi Fi, CD player and fans use another 1/4 of the power generated. The remaining 1/4 of the 12 Volt power is inverted to 120 volts ac and is consumed by ac appliances. We have on the average 36 Ampere-hours at 12 VDC per day of power available, depending on hydro and solar panel output. Disregarding about the power losses due to power inversion and charging, the following chart was devised. INSERT PIE CHART Power is monitored via a metering panel which tells voltage of battery bank and amperage being consumed. Amps and Volts output of hydro and solar panel are also displayed. The metering panel was built with analog meters and is flush mounted in the wall above the circuit breaker cabinet. It is most helpful to see what's happening via gauges, especially hydro charger, because its current output can easily be translated into water output (gals/min). There is no controller because amps produced are small enough that the battery bank can not be over charged. INSERT FLOW CHART System Cost HydroCharger IȘ - $500.00 35 Watt Solex panel - $300.00 2800 Watt Yamaha gas generator (used) - $400.00 (6) 6 Volt DC batteries (2 used) - $300.00 Trace 1512 inverter - $1,100.00 500' of 1 1/4" PVC pipe - $200.00 Monitoring panel, circuit breakers, wiring, outlets, how to books & publications, fans, light fixtures and miscellaneous = $1500.0 Total Equipment Cost = $4,300.00 The actual cost was greatly reduced due to the State and Federal Energy Tax Credit which saved us approximately 40%. This incentive to save energy and use renewable energy sources has sadly expired. The cabin, which is 600 sq. ft. was designed and built with this power system as an integral part. It took us about 400 hours to design and install all electrical components of the system. I would venture that a professional could have done it in half the time. Ideas and Ramblings Our energy needs are also met by using propane for refrigeration, cooking and hot water. We have an Aqua Vac on-demand hot water heater, supplemented by a small water heater in the woodstove. We use approximately 200 gallons of propane a year. Our Thelin Thompson T-1000 woodstove is thermostatically controlled by a 12 Volt feron damper switch and is the winter space heating source for the cabin. The U.S. average power usage is approximately 10,000 Watt-hours per day. By being conservative and designing a small home's lighting and electrical needs efficiently, we manage to be comfortable on approximately 700 Watt-hours a day. In the future we plan to install another HydroCharger IȘ downhill from our cabin and recycle expelled water from the first hydro unit to operate a second unit. It will have 40 feet of fall and be 140 feet away. It is estimated that power generation will increase 50% to 60%, this will enable us to run an efficient automatic clothes washer and color TV. Endorsements Sam Vanderhoof and Ron Kenedi, Photocomm, Inc., Independent Power Division, 930 Idaho Maryland Rd., Grass Valley, CA 95949. Manufacturers of the HydroCharger IȘ. We received valuable advice, great components and excellent service after the sale from Sam & Ron. Thanks! Jon Hill, Integral Energy Systems, 105 Argall Way, Nevada City, CA 95959. Jon has helped us numerous times with products and advice. His workshops on alternative energy and hot water production are great! Trace Engineering, 5917 195th NE, Arlington, WA 98223. We own the Trace Model 1512 Inverter. Everybody knows the Trace is the greatest. "How To Be Your Own Power Company", Jim Cullen. A guide to low voltage technology and alternative power design that was invaluable in developing our system. "Basic Home Wiring Illustrated" by Lane. Introduction to basic electric terms, system design and construction. For the do-it-yourselfers from Sunset Books. Electrical Independence Booklet Series by David Cooperfield. Well-Being Productions, POB 757, Rough & Ready, CA 95975. This series of booklets on electrical independence is most helpful.