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Portable Electric Generators 101

DEAR TIM: I've had it with power outages here at my home and I've decided to get an electric generator. I've got several complicating issues. For starters, my budget is tight. Second, I want this generator to be multi-purpose and take it on family picnics and camping trips. The generator needs to be quiet. What are my options? Can I satisfy all of my wishes and have clean power that won't hurt my sensitive electronic devices? What can you tell me about these small generators? Kathleen K., Boulder, CO

DEAR KATHLEEN: I've got great news for you. You can get a new portable generator that will satisfy all your requirements! What's more, if you lug in multiple bags of groceries on a routine basis, I believe you'll be able to carry one of the generators a short distance with moderate effort on your part.

As with many things, advancements in technology and micro computers have allowed electric generator manufacturers to produce small generators that produce stable and clean alternating current using an inverter inside the machine. Most new portable generators have an onboard computer that converts the direct current from the generator to a very stable alternating current that will not harm your sensitive electronics and appliances.

This easy-to-carry electric generator can get you out of a bind in a power outage or make a camping trip or picnic more enjoyable. Photo Credit: Tim Carter

This easy-to-carry electric generator can get you out of a bind in a power outage or make a camping trip or picnic more enjoyable. Photo Credit: Tim Carter

I know this for a fact because in the past two weeks I tested two different portable generators using a sophisticated oscilloscope to measure the quality of the electricity being produced by the generators. Guess what? Both machines created a more perfect sine wave on the scope than the electricity coming into my home from my local utility!

Here's the scoop on the portable generators. Size does matter. The bigger the generator, and all it's combined parts, the more power it can produce. If you want portability, meaning a generator you can carry like a five-gallon pail of drywall compound, then you sacrifice total power output.

The generators I tested weigh about the same as a pail of drywall compound and produce 2000 watts of power. That may seem like a lot of power, but it's not when you think about the giant standby generator I have next to my garage. This generator comes on automatically if the power fails at my house and will produce 17,000 watts. You can purchase generators that produce far more power than that if you desire. My standby generator weighs hundreds and hundreds of pounds.

Since your budget is tight, you'll probably be able to get one of the 2,000-watt machines. Even though it's power output is not the highest, you can still power many things with it. For example, here's the running wattage of some common tools or appliances:

  • cell phone battery charger - 25 watts
  • furnace fan blower - 700 watts
  • electric crock pot - 240 watts
  • video game device - 40 watts
  • refrigerator - 550 watts
  • water well pump - 575 watts

Briggs & Stratton


What I love about the new portable generators is how they automatically adjust the gasoline motor speed in relationship to the power being requested by the devices you have connected. If the generator senses little need for power, then the gasoline motor runs at a lower speed using less fuel and making less noise.

The new generators are also very quiet, even when running at full speed. When you take them on a camping trip or a picnic, you'll not have to scream to be heard in a conversation.

Generac

The issue with small generators is what's called startup power. Certain appliances and tools have a very high starting wattage. You may have seen this in your home on occasion when a refrigerator, washing machine or air conditioner turns on. The lights in your house may momentarily dim when the electric motors in these things draw lots of power to start spinning.

A portable generator putting out only 2,000 watts can't handle the start-up demand of many things, so you'll have to check into that to see what you can and can't power when your house power goes off.

You'll discover you can use a portable generator at your home in a power outage, but you'll be busy. You'll only be able to power a few things at a time, so you'll be switching out extension cords as you produce your own rolling brown outs within your home.

The portable generators, by default, have smaller fuel tanks so if you have an extended power outage, you'll be refueling on a more frequent basis. Follow all safety guidelines when refueling a generator and NEVER EVER operate a portable generator indoors, in a garage, near an open window, etc. The carbon monoxide produced by the gasoline engines can and will kill you. Be CAREFUL and read all safety instructions.

Column 1050

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2 Responses to Portable Electric Generators 101

  1. The limitations of these portable units for home use in a outage is that they don't really help with water pump, furnace fan, etc because those don't run on extension cords but correct me if I am wrong. I have a 5000 watt gen for that and had a friend wire into the house panel. I labeled the circuits I wanted (furnace, water pump, refrig and living room), and only turn those on when I switch over. I do it manually, but as you know, you can get an automatic installation done which is safer and much more expensive.

  2. Eric, what you have done is a good way to power those items you mentioned, except I would clarifiy that for safety reasons, and most utility regulations, there should be a some type of interlock on your back fed system. This would only allow the generator power to come in if the utilty is disconnected from you system. This is a safety feature for two reasons: 1. you're not able to backfeed onto the utility (which your generator couldn't handle anyway), and 2. when the power comes back on, it would be out of sync with your generator and could cause major failure including fire.

    A manual interlock for a breaker panel is a piece of hardware that slides between your utility (main) breaker, and the generator backfed breaker. In order to turn on the generator breaker, you must have the utility breaker turned off, and visa-versa. This interlock makes it work in only that fashion, so it is more or less dummy proof.

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