A portable generator might be a convenience, a necessity, or a lifesaver, depending on the situation. Very often, they serve multiple purposes on job sites, camping trips, and around the home.
Their portability brings electrical power wherever it is needed and isn’t easily available. They show up at tailgate parties, farmer’s markets, community events, and picnics.
The array of features can seem confusing, but some are more important than others.
120 vs 240 Volts
Many small generators provide just 120 volts. When power needs are light and you won’t run any 240- volt appliances or tools, one or more 120 volt outlets work just fine. As the power requirement in watts increases however, 120-volt units become increasingly inefficient.
Larger units generate 240 volts more efficiently and supply it as separate 120-volt circuits. For higher voltage applications, such as supplying certain tools or connecting to the house during an outage, the 240-volt option is important.
If you’re looking at 3000 watts or less, you’re probably fine with a 120-volt generator. Otherwise, look for one that supplies 240 volts.
Low Oil Shutdown
Generators often run for hours without a rest. As they use oil, the level can drop to a point where it doesn’t properly lubricate the engine anymore and damage can occur. A low-oil sensor can shut off the engine and prevent costly repairs or even the need to replace the generator.
Even Better: A fully pressurized lubrication system similar to that found in a car ensures all the moving parts receive a continuous bath of lubricating oil.
A low oil sensor is especially important when the generator will run unattended for long periods. Always check the oil during refueling and top it off to maintain the correct level.
If you’ve ever pulled endlessly on the starter rope for a large engine, you know what a chore that can turn into. Electric starters eliminate this problem. The speed and duration make it very easy to start the engine.
Since your generator will probably spend a good portion of its life in storage, keep the battery charged and ready. A charger designed to maintain a battery without overcharging will ensure it stays ready for use.
Although you won’t find a pull cord on most larger generators, such as a standby unit or trailer model, having one on your home portable is still a good idea. If the battery dies at the wrong time, you can still start the generator if necessary.
Match the number and type of receptacles to the intended to use. On small units, two or three, 120-volt receptacles is usual. As the power capacity increases, expect to find a wider variety of types. A feature like GFCI receptacles is important when you’re running hand-held appliances on extension cords in a damp location.
Look for one or two locking receptacles with a high-current capacity. A 30-amp or 50-amp receptacle is useful for connection to a manual transfer switch and can provide power to hard-wired appliances such as a furnace, well pump, or even an air conditioner.
Most portables run on gasoline and storing fuel for them sometimes turns into an issue. Many local communities restrict storage of gasoline and a common limit is 25 gallons. Gasoline also has a limited storage life and keeping large fuel supplies fresh is a chore.
Some models run on propane (LP Gas) and they eliminate the need to store gasoline for the generator. They use the same tanks as your gas grill.
Keep gasoline supplies fresh with a fuel stabilizer, and only use stabilized fuel in your generator. It prevents stale gasoline from gumming up the fuel system and you can store the fuel for a year or more. Just follow the manufacturers recommendation.
Some generator manufacturers recommend the use of pure gasoline without ethanol additives. It only costs twenty to thirty cents more per gallon, but using it may mean a longer generator life, better fuel economy, and smoother operation.
Purchase ten to twenty percent more power than you need. It allows some leeway for additional loading if necessary. A new tool or appliance might use more power than the one you’re using now.
Remember the difference between continuous capacity and surge capacity. Choose a portable generator that can continuously supply the maximum amount of power you intend to draw. Add up all your electrical loads, then add triple the load of your largest motor. After that, add another ten to twenty percent and that is the size generator you should purchase.
Portable generators are available in capacities ranging from a few hundred watts to models that can supply thousands of watts. Match the generator you purchase to your intended use.
If your intended main use is to supply emergency power during an outage, consider using the right tool for the job—standby generators are designed for exactly this purpose and will do the job better, use less fuel in the process, and do it automatically even when you are away from home.