Need some advice on power setups

Discussion in 'Homesteading Questions' started by adofus, Aug 8, 2004.

  1. adofus

    adofus Member

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    Can anyone offer up some advice or a url on how to setup a generator/battery bank/inverter. What rating on the generator minimum? What kind of inverter? Minimum rating? How many batteries? Type? Anything else needed? I would be running the normal household items, but possibly in a remote area. Thanks for the help.
     
  2. rambler

    rambler Well-Known Member Supporter

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    I will be of no help to you, but there is no such thing as 'normal household items' when it comes to a battery bank & an inverter. What exactly are you expecting to run with the system? A well seems to be the sticky point, will you need to depend on it for running heating equipment, and so on.

    You'll get better replies if you more carefully decsribe the load you will place on the system.

    --->Paul
     

  3. adofus

    adofus Member

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    Hmmm guess I considered "normal household items" pretty self explanatory. Tv (large) , AC, Hot water heater, fish tank (large), stove, refer, washing machine, asst. lights. The whole point of the post is that my knowledge is limited. As I understand it, regardless of the drain on the system (speed of drain on battery), you can power anything if you have a large enough battery bank, up to the limitations of the generator wattage/amperage. I'm guessing based on what I have read in the past that 7500+ watts generator would be sufficient. My confusion comes in with, gas to generator, generator to what?

    But I do thank you for you response rambler. Perhaps the added information will bring more responses as you suggested.
     
  4. Cyngbaeld

    Cyngbaeld In Remembrance Supporter

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    You might want to go to

    www.backwoodssolar.com

    and order their book on cutting down on electrical usage first.

    Then get their meter that you plug each appliance into and check how much power each is using.

    Yes you can run anything at all on a gen set. IF you have enough $$$$$ to throw into it.
     
  5. Runners

    Runners A real Quack!

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    Cyngbaeld is right, first go around the entire house, get the wattage rating off every name plate, and list everything in an excell spread sheet (or on paper).

    homepower.com has this stuff, they MAJOR on power production and conservation. They also have the spreadsheets to do this. There are too many other sites to post with incidence data on wind, sun - but HP magazine has lots of essential data for researching your location.

    Random thoughts from our experiences....

    Every watt of power saved is something like 3-4 watts of power you don't need to generate. Power generation is expensive, power storage is even more expensive. We have a large battery bank, -48VDC that I've aquired from work (telecommunications). A typical AGM (absorbed glass matt) battery will last 15-20 years if the drawdown is 10% or less. Draw the same battery down 50% and the lifespan is shortened to 2-3 years. LOTS of batterys and low drain - but more maintenance. The harder you hit 'em, the quicker they fail. Nothing lasts forever - and it usually quits when you least expect it or are prepared...

    A word to the wise, if you're serious about alternative energy, find the cheapest batteries you can find, and LEARN how to take care of them. More expensive batteries are destroyed through well meaning ignorance than accident. Golf cart batteries are cheap @ $45 each. AGM batteries have less capacity than flooded cells (golf cart), but they are "maintenance free"... Either one can be quickly ruined by over/undercharging, deep cycling and sulfation. You'll only get back 80% of the power put into a battery... if you're lucky, and they also self-discharge.

    Heavy wire, for lower voltages. I have a program we use for wire sizing, just plug in the distance and voltage drop, it spits out the gauge of wire to use. We typically size for less than .5 volt drop for a -48VDC system. Heavy, thick wire does increase effeciency, just like higher voltages. Series battery strings equalize and last longer than parallel strings. Higher voltages also save by using smaller gauge wire. (got years of experience on battery plants...) High voltage & lower amperage is no more dangerous than low voltage and higher ampacity. Welders are low voltage, high amperage...

    Don't rewire your house for 12VDC. or any other voltage. Forget the idea - it'd only reduce your home resale value and besides the electrical inspector & insurance agent would make your rip it all out.

    Generators... skip the cheap stuff. Propane starts great in cold weather, unlike diesel & gas. Any gas generator can be converted to dual fuel (gas / propane) with a simple add on kit. I would size the generator @ 1.5 times your total maximum load. As most generators approach full load, the frequency, voltage can drop - destroying UPSes, well pumps, furnace motors and voltage / frequency sensitive equipment (like your TV)... During last year's hurricane, we lost an expensive UPS to a cheap genset. Water cooled gensets are inherently quieter, and with a heat exchanger can both provide power and hot water, maybe some heat. Air cooled gensets can provide some heat.... but an exhaust leak can be deadly.

    Solar panels are currently in short supply, prices are up. Hydro and wind are a different animal, the excess power MUST go somewhere, espically with hydro. Big water tanks and electric elements or resistive loads work well. Like with any generation system, even a solar heating system, as you build it, figure out where the excess heat, power, cooling, etc., is gonna go. Last thing you want is boiling anti-freeze, smoking wires or a wind or hydro plant running wild (high voltage)

    Inverters - buy ONLY sine wave units that can be stacked. All the cheap junk with square waves, modified sine waves will make your TV set so wacko it won't be watchable. Your radio will whine like a sick puppy or buzz and pop so terrible, even your car will pick it up. Stackable units generally start around 2000watts, and cost as much. If you need 6000 watts, you get 3. Some can surge better than others - essential for starting motors & pumps. More 48VDC units are coming out, a good thing. Some companies have experienced problems with service, design and $$$. Do your research well before you fork out the $$$ - big companies don't automatically mean good products.

    Water storage capacity is as essential as power storage. We replaced our 10 gallon bladder tank with an 86 gallon tank. Instead of one toilet flush, we get several when the power fails. Convert your well pump to a solar well pump, and let the pump run when the load is low, when the solar panels are producing.... building up water storage in a big elevated tank over time instead of just on demand.

    Most of all, look hard at the total effeciency of your appliances, washing machines use power AND water. Big appliances like stoves, water heaters, dryers, furnaces and air conditioners consume HUGE amounts of power. Each demand can be met through 2-3 different sources, ie., electric, gas, heat. Some energy users can really be reduced by simple & cheap conservation methods, insulation, ventilation, or adjusting your thermostat. Even wise placement of landscaping materials, trees, bushes and powerless turbine ventilators and dramatically reduce your AC. A typical desk top computer uses 300 watts + 200 watts for the monitor, 500 watts! A laptop uses less than 20 watts. A typical 60watt light bulb produces the same amount of light as a 14watt flourscent "twister" bulb. Sure, it cost more, but not near as much as the extra batteries, solar panels do!

    Lastly, consider multiple systems for power / energy generation. When the wind isn't blowing, it's sunny. When it's windy, it usually isn't sunny. They compliment eachother. A single lightning strike can just ruin years of work and investment. Have backup sources of power READY TO GO, before you disconnect from the grid. We actually have a propane 10KW & a gas 5KW gen set. A gas + and electric water heater makes more sense in storage and as a backup than just one or the other. We are STILL converting and decreasing our energy consumption, take your time, learn (subscribe to HomePower), and ask lots of questions!
     
  6. 12vman

    12vman Offgridkindaguy

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    Bravo, Runners.. <clap-clap-clap>
    Great advice! Great description!... :worship:

    I'm way on the other side of the spectrum.. I'm off-grid and operate everything I can on 12 volt d.c. I only invert when I need to. 98% of my house runs on d.c...

    Again, Great response..

    Don
     
  7. rambler

    rambler Well-Known Member Supporter

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    As I was guessing. If you have very much money, then anything is possible, sure.

    If you need to work within a reasonable budget, you need to plan much, much, much more closely on what you plan to use, when, & how much for your electrical needs, and then design a power system that meets those needs.

    If it were simple, easy, & cheap, everyone would have their own power plant.

    You would need to greatly reduce your power needs to effectively use a gas power generator/ battery bank/ inverter. An electric hot water heater?????? Not seriously, unless used part time as a resistance load to a windmill or solar over-charging situation.

    --->Paul
     
  8. Runners

    Runners A real Quack!

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    I counted, we have 6 banks @ -48VDC of 70ah ea.
    We also have about a dozen 12VDC of 100ah ea.

    Most of it is AGM batteries, almost idiot proof (probably not enough for me, though!)

    Problem I have with the majority of 12VDC or DC appliances in general, electrical noise from the brushes. I like to listen to AM radio, like at night when I can pull in stations from long distances. Even on grid power, shutting down practically everything and using the long wire antenna really helps.

    Don, you've got a dream setup, if you built it that way - a nightmare if you had to convert it from a conventional house. I'm already built, so we'll invert to 240VAC from the -48VDC banks.

    My problem with 12v appliances is they lack sufficent power - or to gain enough power they require HUGE thick cables to carry the increased amps.

    Start with a 250w blender/mixer
    120 VAC unit, like you buy in a store, standard appliance, uses 2 amps & can run on a skinny 16 gauge cord.
    12 VDC unit, harder to find and more expensive, uses 20 amps and needs a 10 gauge cord (thick) to produce the same amount of power.

    One other thing, adofus...

    Don't get sucked into the unproven, back of the comic book advertizing junk science. My car *really* can get 300mpg - sure, when I push it. And those "gravity engines" or "cold fusion reactors"...? No, it's not big oil, Bush or greedy capitolists supressing their development, they just don't work.

    Subscribe to HomePower magazine, it's written by Engineers that have decades of real experience. (just ignore the politics, and you'll be alright)

    .
     
  9. I tracked our utility bills for a year, entered all the data on a spreadsheet, average wind velocities, solar days, etc. Recommend you do the same.
     
  10. adofus

    adofus Member

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    Runners,

    Thanks for taking the time to post an informed and insightful rundown. The information was enlightening and will give me much to think about. Everyone else, thanks for advice...Guess now the fun begins of charting usage etc.