There are three major reasons that wind, solar or hydro-electric systems are impractical for some folks: not enough wind, too many cloudy days, and no stream. In that order.
What does that leave them with? Using a generator. Ugh? Not necessarily.
An independent energy system that uses a generator as its primary power source can be efficient and cost-effective in its initial setup. The key is to make it part of a system instead of a sole source of power.
Most important in making it part of a system is full utilization of the generator’s potential. A system that uses only a small portion of the generator’s capabilities and stores little or no power for the times when the generator is off-line is a disaster.
Managing and storing electricity are essential to success
There are two elements essential to the utilization of the generator’s potential:
- managing generator loads
- storing electricity.
Managing your generator loads means that you operate the generator only when lots of power is required, as on the days of the week you do your laundry, vacuum the house, operate your shop, pump irrigation water, and/or other heavy use. Then while the generator is running anyway, it can also operate an industrial-strength battery charger. The charger will charge the batteries that run the lighter loads of the house when the generator is not running.
There will, of course, be times when you will need to run the generator for a single purpose. The point is to develop a schedule of activities that makes it easy on everyone in the household to co-operate.
The ability to store electricity is what makes it all possible. Deep-cycle batteries are available in many forms and capabilities, with prices to match. The good old lead-acid batteries, like those used in golf carts and electric fork-lifts are still definitely worth considering because of their low price.
The most important factor in choosing your batteries is the total storage capacity. Your batteries must be able to handle the total load of your system between run-times of the generator.
When the generator is off-line, the low-voltage direct current (DC) supplied by the batteries is changed to regular 110 alternating current (AC) by an inverter. For this system to run at peak efficiency, there must be enough battery-storage capacity to run your house between the times you need the generator for heavy-duty use.
Gas vs. Diesel
For a permanent electrical system, the cardinal rule of generator shopping is do not even consider a gasoline-powered unit that runs at 3600 rpm … for several good reasons:
- Almost all of these machines are built for intermittent use only.
- Almost all of them will self-destruct when used for prolonged periods at even modest loads.
- Almost all are optimistically over-rated.
For example, we borrowed a popular-brand Japanese generator to use while our good old industrial machine was down for its first repair after years of service. Our old, industrial generator was rated at 3500 watts and would easily start any power tool in the shop even when the air-compressor was running. The borrowed unit, resplendent in chrome razzle-dazzle and complete with automotive-style operating panel (even an ignition key!) was rated at 5500 watts—but it would not even start the compressor. It just huffed and puffed, lugged down, and popped its circuit-breaker.
The generator part of hardware-store gensets (generator sets) is the absolute minimum quality that the manufacturer can get by with and still rationalize the advertised output. Neither the voltage nor the frequency is stabilized very well.
Another reason to avoid the gas-powered generators for permanent installation is noise. A 3600 RPM (revolutions-per-minute) gasoline generator, running under load, is incredibly noisy. Someone once asked me if I had ever heard a certain new imported generator run. He said that the dealer fired one up inside the showroom and it fairly whispered. But the dealer did not plug anything into the generator to bring it up to its normal operating speed.
Buyer beware. Many of the bigger (and recently, not so big) high-speed gas generators have an idle feature which allows the engine to slow way down when there is no load on the generator. But the instant the generator senses a load, the machine comes up to its full-scream speed.
These machines do have a useful application. A gas-powered portable generator with an idle-down feature is a great tool for temporary use on a jobsite, or anywhere else power tools are used in an frequent-but-intermittent manner. You can just leave the generator quietly idling along, and it will instantly come up to speed whenever a tool is switched on.
If it seems wasteful to leave it running when not in use, weigh the convenience of not having to restart it each time a tool is needed. Also, particularly in cold weather, it is easier on an engine to let it idle between run-times than to make it go through the continual temperature excursions that accompany start-and-stop operation. But remember that these machines are neither intended for nor suited to continued operation at full output.
Good generators…
Some of the best industrial-quality (1800 RPM) gasoline-powered generators available have the bonus of also being electric welders. A good-quality arc welder can be a real asset on the homestead. Even if you don’t know the first thing about welding, having the machine available makes it easy for someone who does know how to use it to do any repairs that require welding.
Check your yellow pages for a welding-supplies dealer who handles Miller products and ask to see the lineup of welder-generators. They come in various outputs and all have excellent engines designed for continuous operation at full-rated output. These machines run at 1800 RPM in “generator” mode and at 3600 RPM in “welder” mode.
We ran our home, office, and shop business with a Miller welder/generator for years. Its engine just loafed along, producing its full-rated power.
There are other manufacturers of combination welder-generators, too. Be careful in your selection to find a machine that runs at 1800 RPM in generator mode. Many run at 3600 RPM all the time.
There are other gasoline-powered, 1800-RPM, industrial-quality just-plain-generators available, and they will usually be powered by Onan, Kohler, Wisconsin Robin, or possibly Briggs & Stratton “I/C” Series engines. Onan makes an excellent 4.5 kilowatt unit designed for mobile applications, like utility vehicles and motorhomes. It is well suited to permanent installation, and sells for about $2600.
…and better diesels
The most efficient and maintenance-free engines of all are diesels. Diesels have no ignition systems, carburetors, nor spark plugs. They burn lots less fuel per horsepower/hour than do gasoline engines, and their exhaust is devoid of many of the toxic emissions of gas engines.
Diesels are simple in design and extremely durable. With few exceptions, properly serviced diesel engines will run for years and years before needing an overhaul.
But there’s always a catch. The catch is that diesel-powered generators in the small sizes required by the average homestead are expensive. Onan has recently introduced several versions of small diesel generators. They come in sizes from 4.5 KW on up, and are powered by Onan or Kubota engines, depending on the model. They all run at a leisurely 1800 RPM.
The Onan diesel engine is air-cooled and somewhat noisy. The Kubota 3-cylinder engine is liquid-cooled and for a diesel, amazingly quiet. Both engines have excellent service reputations. The sizes up to 7.5 KW are most useful in homestead applications, and the prices range from about $6000 to $7000. Ouch, right?
Our local generator dealer says that he doesn’t even stock diesel generators any more, because people are so blown away by the prices that they run to their nearest discount store to drop $2000 or more for a garden-variety, light-duty, 3600 RPM gasoline-powered generator of the self-destruct persuasion. Read More
