Getting Ready For Winter Windy Dankoff Independent power system users and dealers should check the following items. After all, it's easier to do it now- before everything is froze up, iced over and buried in snow. Photovoltaic Array Inspect and tighten mounting bolts and wiring, test output, and tilt for winter angle. Play attention to mechanical connections in the panel's wiring boxes. Trackers Oil bearings, check mounting bolts and shock absorbers. Engine Generators Give the engine an oil change, replace the air and fuel filters. Low temperatures cause water condensation in the fuel tank. A good water trap & sediment filter is cheap insurance for a gas engine and required on a diesel engine. Check the ignition system and the spark plugs. If the engine uses electric starting, check its battery and clean its connections. Wind Generators Make sure that the tower's guys are solidly connected and properly tensioned. Check the propeller, bearings, brushes and slip rings in the wind generator. It's much easier to replace them before the tower is iced over. Hydro-Electric Check the trash racks for damage. Winter rains bring debris downstream, so be prepared. Check the thermal insulation on water lines to prevent freeze-ups. Check the brushes and bearings in the Hydro's electrical alternator or generator. Charge Controller Check regulator voltage settings, check voltmeter accuracy with digital meter. If your controller doesn't automatically compensate for temperature, then you can set it a few tenths of a volt higher to compensate for cold lead-acid batteries. Lead-Acid Batteries Test each cell of each battery with digital voltmeter or very clean hydrometer to spot potential failures and check need for equalization. If the cells in your pack differ by by 0.05 Volts or more, then equalize! Wash away accumulated moisture and dust from battery tops, use baking soda solution to neutralize acid deposits. WARNING, do not allow any of the baking soda solution to enter the cells. Clean or replace corroded terminals; coat with petroleum jelly. Check water levels and refill with distilled or deionized water. Inspect venting (check for insect nests in vent pipes). Check insulation/shelter from cold. Wiring Check for proper wire sizing, tight connections, fusing, safety. Grounding and Lightning Protection Install/inspect ground rods and connections, ground wiring (see HP#6). Loads/Appliances Check for "phantom loads" and inefficient usages. Example: Does your furnace thermostat hold your inverter on 24 hours a day?--See below! Lights Look for blackening incandescent bulbs; consider Quartz-Halogen or Fluorescent replacements (see HP#9). Winter days increase the use of all lights. Now is the most cost effective time to install efficient lighting. Inverters Check adjustments, settings, connections. NOTE: Inverters with Battery Charger Option should have charge voltage set around 14.5 (or 29) volts if a generator is to be used for charging. (Most come set lower, assuming utility-line charging at a slower rate.) See your manual. Water Supply Check freeze-protection, pump maintenance, pressure tank pre-charge. Freeze Protection And Heat Tapes Electric heat tapes are a popular way to prevent water pipes from freezing under mobile homes, on solar water heaters, and in well sheds. Where heat tapes are a necessary evil, here are some tips to MINIMIZE THEIR ENERGY USAGE: Insulate Use foam pipe jacketing, fiberglass ANYTHING that insulates and PLENTY OF IT! Be sure cold air and moisture are sealed out. Less Is Best Use less heat tape than recommended, with fewer, wide-spaced coils. With extra insulation,you won't need much heat. Frostex And Line Voltage Thermostats Use "Frostex" round heat tape, it is the most efficient, but you may wish to add a line voltage thermostat to disconnect it in warm weather. (A Line Voltage Thermostat is one that is designed to handle power directly from 120 vac. A recommended one is Dayton #2E158, available from W.W. Grainger or from any electric or heating supplier. Like most other switches, it will also handle its rated amperage (22A) at 12 or 24 VDC. Its 35-90 degree range makes it appropriate for use with heat tapes and furnaces, and coolers and fans as well. The Dayton 2E158 allows switching power on OR off with temperature rise, so it also works for switching FANS on at high temp for circulation of solar or wood heat. If you use a conventional flat tape, be sure it has a thermostat on it. The thermostat may be tucked into the insulation closer to the pipe so it won't turn on until cold penetrates into the insulation. ac or DC? A 100 watt Statpower or any good inverter will power heat tapes, or you can convert heat tapes to 12 or 24 volts! ac to DC - Here's How If you're not afraid to cut and splice, here's how to make a low voltage heat tape. 1) Buy a conventional FLAT heat tape with thermostat. 2) For 12V, measure 1/10 of its length from the thermostat end and CUT. For 24V, use 1/5 of its length. 3) Strip the cut end and twist the two inner wires together. Protect the end with silicone sealant and/or tape. You now have a low voltage tape with thermostat. It will draw the same wattage per foot as the original. The neon indicator light won't work, but an ammeter will indicate current flow. The remaining tape may be cut into more low voltage tapes by splicing lamp cord to one end, and tying the other end together (using crimp connectors). You will need to add a thermostat if desired. One Line Voltage Thermostat can switch many tapes on and off. Backing Up Install heat tapes even where you don't expect a freeze. They make it easy to thaw surprise freezes without digging, ripping out insulation, etc. Thermostats are optional on these "back-up" tapes. Furnaces and Controls - Thermostat Circuits & Power Usage Most central heating systems use a low voltage circuit through a wall-mounted thermostat to tell the furnace when to turn on and off. The low voltage is derived from a small transformer which is powered constantly. Its usage is only a watt or two, but in an alternative energy system that may be a significant load -- if it is the only ac device that's running, it is adding a constant 6 to 12 watt draw just to keep the inverter "up". That amounts to the wintertime energy output of 2 or 3, 50 watt PV modules, costing over $300 each! The Answer If yours is a system where the inverter spends most of its time off, it is worth adding a Line Voltage Thermostat to your furnace circuit. You may order one from a heating supplier and have it installed ON THE ac LINE to the furnace controls. Also bypass the original thermostat. This way when heat is not needed, all power is cut to the furnace transformer. A small "limit switch" thermostat may be also added to sense heat in the furnace and keep the blower on until "left-over" heat is exhausted. Material cost of these modifications is under $30 and wiring is simple. Temperature Adjustment When nobody's home, you only need to prevent your home from freezing, so water pipes, fixtures and bottles won't freeze. Most heating thermostats stop at 50¡F, but fuel may be saved if the temperature can be lowered to 40¡F or less. Electric power is saved, too. We suggest replacing common thermostats with the Line Voltage Thermostat discussed above. Windy Dankoff, Flowlight Solar Power, POB 548, Santa Cruz, NM 87567 ¥ 505-753-9699