Portable Generators: Which one is right for you?

by John Boch

(GunNews) – More and more folks are considering purchase of a gas-powered portable generator (“genset”) in case of power outages, or for use at job sites, campsites or other uses.  The array of choices can be daunting, as can be the price tags, but a little knowledge and understanding can make a better selection of the right generator for your needs.

First up, identify how much and what kind of electricity needed.

Which devices and appliances do you really need if the power fails for more than a few hours?

How much current do they consume?  Add those loads up.  Hint: most devices state their load in either amps or watts, typically near where the cord meets the device.  If the load is stated in amps, multiply that amperage number times 120 to get watts for 120v items, and 240 for 240v devices.   You can also use a "Kill A Watt" meter which will tell you exactly how much wattage your devices use, both on start-up and while running (or idling).

You might be scratching your head about the "what kind of electricity" mentioned a moment ago.  Cheaper generators and inverters produce a "modified" sine-wave alternating current (AC) electricity.   This will work in a pinch but it causes motors and transformers to run hot and some electronics may not run at all with modified sine-wave AC.  (Hint:  If you're running your refrigerator on modified sine-wave AC in an emergency, you might be wise to put a small fan blowing under it to help cool the compressor to avoid burning up the compressor motor.)

The new "inverter" generators produce a pure sine-wave AC, at rock-solid voltages, just like the utility companies deliver to your house.  These generators will run finicky electronics and your AC motors won't notice any difference from the utility power they are accustomed to consuming.  The inverter gensets are also much quieter.  The smaller your noise signature of course, the less attention you draw to those around you without electricity to the fact you have power.

Of course, it is never just that easy.

Electric motors require extra current to get started. How much?  It varies by size and type of motor, but may be as much as twice the running load.  If you have a critical motor (such as a deep well pump), you would be well to have a professional measure exactly the starting load so you know exactly how much power you're going to need.

Once you’ve identified your load requirements, add 33%.  You shouldn’t continuously run any generator its rated capacity or you will reduce its life expectancy.  At the same time, don’t get too much more generator than you need or you may find yourself running out of fuel before you run out of emergency.

Gas-powered, portable light-duty generators

For the purpose of this article, we’re going to look more closely at gasoline-powered portable generators as they are most prevalent and affordable for emergency and light-duty applications.

If you’re expecting to use the generator for sensitive electronics and computer-controlled devices that require rock-solid voltage, you would be best served by one of the “inverter” generators.  Their pure sine-wave 120-volt AC has no voltage sags and other issues associated with older “traditional” generators which produce a modified sine-wave AC current.

The inverter units are also much smaller and lighter than conventional sets.  Again, as an added bonus, motors and compressors run cooler with pure sine-wave AC.

The downside to the inverter generators is the increased cost:  they are usually about at least twice as expensive as similar output traditional generators, but owners of these inverter units rave over their remarkable fuel efficiency and super-quiet operation.

Some recommendations.

For those on a very tight budget, the Harbor Freight 800W or similar is a decent little entry-level generator for those needing a small, portable unit.  On sale now and then at Harbor Freight for $89 from its regular $129 price tag, it’s hard to beat when it’s on sale.   Grab a 20% off coupon out of your American Rifleman magazine or Google “Harbor Freight 20% off coupon” images on the internet (and print out said coupon) for an even better bargain!

It’s earned overwhelmingly positive reviews from its owners.

The downside to this unit is its fairly meager 800-watt output and that it consumes a 50:1 fuel to oil mixture instead of straight gasoline in its two-stroke engine.  It runs through about a quart of fuel an hour on a 500 watt load.

It's also noisy.  Think lawn mower noisy and then some.

The inverter units from Honda remain the gold standard.  The EU2000i is a wonderful little unit rated for up to 2000 watts.  It’s remarkably quiet, light (about 50 pounds fully fueled), and frugal with the fuel.  The EU2000i, under a 500 watt load, will run about eight hours on a gallon of fuel.

The EU2000i sells for about $1000, although Mayberry Sales and Service out of New Jersey had the 2000i (before Hurricane Irene swept through) for $899 delivered.

Yamaha has similar approximately 1000- and 2000-watt inverter units that might even be better than the Hondas.

For those who want a quality inverter generator but don’t want to spend a thousand dollars, consider the Champion 2000w inverter generator.  It is cube-shaped and sells for about $550.

Champion has a good reputation for great products, good customer support and affordable prices when it comes to all of their generators.

If you have a well pump or other appliances that need 240v, then you’re going to need a larger unit than these we’ve mentioned so far.  Larger units are heavier (well over 100 pounds) and often have wheels to facilitate a single person moving them.  They also use a lot more fuel.

Champion has a series of conventional units in the 3000-7000w range (priced $350-$800ish).  These also share a reputation for reliability.
These should have no problem running your well pump and a forced hot-air furnace, refrigerator, sump pump and maybe some lights for a short-duration emergency, but like with all modified sine-wave generators, you should keep an eye on motors for overheating issues.

Once you’ve brought your new generator home…

Crack open the instructions and read them.   Add oil to the generator, as indicated.  Pull the air filter and work a few drops of motor oil into it so there’s a very light coat throughout the entire filter if that’s what the instructions call for.  Make sure the spark plug is seated snugly.

Your generator may have been test run before shipping.  Treat some fresh fuel with Sta-bil or PRI-G and give it a test run for a few minutes.  These stabilizers will keep your fuel from going bad for a year or more.  Untreated gas will, in as little as a couple months, leave a varnish-like residue in the carburetor.  This will cause rough operation or worse.

If you’re going to store gasoline for emergency use, treat and store winter blend fuel.  The refineries add more of the high-end ingredients in colder months in order to make starting easier in cold weather.  Add your stabilizer, fill the cans and tightly cap them (and label with date filled).  Keep them in an unattached garage or some other structure away from your home.  Stored this way, your gasoline will remain usable for over two years (but rotate annually anyway).

How much gas to store?  

Well, there’s rules and regulations about storing gasoline residentially (you’re generally limited per fire codes to 25 gallons in an unattached structure), but a good rule of thumb is that you’ll consume at least .2 gallons per kilowatt hour of generated electricity.

You’ll use a little less with the new inverter generators and a more with some of the older, conventional models.   It’s up to you to determine how much electricity you will need for how long, and by extension, how much fuel you’ll need to store.

Speaking of fueling:  Don’t fuel a running unit and don’t fill the tank to the top.  Leave a half-inch gap above the fuel to allow for fuel expansion in the tank as the fuel gets warm.  Clean up any spills before trying to re-start your unit.  Use common sense.

Security

Before an emergency or extended power outage pays you a visit, think security.

Get a sturdy cable and stout padlock to lock your generator down, so to speak.  This will slow ethically-challenged individuals from walking away with your power source.  Another tip:  buy a wireless driveway alarm from Harbor Freight ($15ish on sale).  These detectors chime a receiver when they detect movement.  Mount the detector near your generator to notify you of prowlers, day or night.  Remember, the bigger the noise signature, the more strangers know you’re comfortable when they are not.

Transfer boxes, extension cords and suicide cords.

For most short-term purposes, it’s probably most cost effective to simply run a couple of heavy-duty extension cords into your home.  I like to use a GFCI pigtail at the genset to minimize the risk of electrocution if I’m running my generator in anything less than ideal weather conditions.

Use larger-gauge cords, no longer than you really need.   12 gauge cords are recommended for loads exceeding 15 amps for short distances.  10 gauge cords should be used for loads over 20 amps or long distance runs.  Use heavy-duty taps if you need to plug in multiple items.

Transfer boxes can be (professionally) installed to energize your entire home safely with a generator, but these usually cost about $1200 to install.

Suicide cords refer to home-made extension cords with two male ends, used to backfeed electricity from a generator into a home’s electrical system.  This is rife with the potential for epic failure.  You can inadvertently electrocute power company linemen, yourself and/or family members.  There’s also fire hazard from over-loading the cord, plugs, circuits and other issues.

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Sure, in good times a well-rested individual may remember all the steps, in order, to pull off backfeeding without incident, but power outages don’t usually come at noon on a warm, sunny day.

If you didn’t properly isolate your home from the grid while backfeeding, the fireworks show at your generator will be spectacular when the utility feed returns, especially with a tank of gas on top of it.

Spare parts.

Go visit your local auto parts store and pick up an extra couple of spark plugs, along with several quarts of the recommended oil.  Pay attention as the cold-weather oil and spark plug recommendations may be different than the summer ones.

If you have a new unit, make sure you change the oil after ten hours or so and again a second time after the next ten hours.  Tiny bits of abrasives and metal are shed when a motor is “broken in” and if you don’t get those out of the crankcase, they will shorten your generator’s engine life.   Run the machine for five minutes or so before you do the oil change as warm oil will wash out the trashy stuff much better than viscous cold oil.

You’ll also want to “exercise” your unit every month or two for five to ten minutes, putting it under a modest load after a two-minute “warm up”.  A 500W quartz lamp makes a good load.

Bargains.

Watch Craig’s List for bargains on generators if you’re not in a rush to pick one up.  Use their search function and peruse the listings.  These deals often appear after big storms when people have purchased sets and used them only briefly and now they want to unload them since the stores won’t accept returns.

Hints for buying used:

•  Take a quartz halogen light (300-500W) to test the generator’s output and consistency.  If it flickers a lot or fails to light, that’s not good.
•  Before they offer to start it up, check to see if the engine’s warm.  If it is, they may have difficulties starting it and they may have “warmed it up” to mislead you about how easily it starts.
•  Check the oil level too.  Too much, too little or very dirty oil is a sign of poor maintenance habits.
•  Old fuel will foul a carburetor and make a generator hard to start and rough running.  Neophytes to generators seldom treat their gas with Sta-bil or PRI-G and if it’s been sitting around for more than a couple of months, the fuel should be discarded (as in poured out, not run through the motor).
•  If the motor runs fine but there is no electrical output, the generator field may need to be flashed.  You can do this yourself but that’s beyond the scope of this article.  You can Google “flashing a generator field” for a how-to.

In short, there are lots of options in selecting a generator for your recreational, work or home use.  Like firearms, they should be treated with respect and proper safety protocols followed for safe use.

Used properly, a good generator can make a big difference in a power outage, in terms of morale, clean-up and more.  They can safely run critical electrical items you’ll need in an emergency at home or at your business, preventing property damage and perhaps even saving lives.  They’ll also provide convenience in remote locations for work or fun.