The Basics for Generating and Storing Power

More than ever, our civilization relies on electrical power for everything: lighting, entertainment, communications, security, heating / cooling, cooking, food refrigeration, the list goes on and on. Our reliance on the electrical grid has made electricity critical to our lives.

Short power outages (under 12 hours) have resulted in widespread traffic chaos, hospital evacuations, and even civil disorder. Multi-day outages can adversely affect water and sewage systems, supermarkets, gas stations, and cellular phone systems.

Even big cities like New York can suffer from power outages. The massive East Coast blackout of 2003, stranded thousands of people in airports and subways, hospitals were affected, and some took advantage of the crisis with a fair amount of looting.

The Basics

The subject of how to generate and store power is huge and I am only scratching the surface here in this article. As a result, I’m not discussing solar, wind, or small-hydroelectric power. All three have pros and cons that are discussed at length in print and online. Here I will concentrate on what most people can easily put together in a suburban environment with a reasonable investment in time and money.

Preparing for extended power outages is a little more complicated than you’d think. These days, having a generator is hardly the ultimate in power generation…EVERYTHING in our lives consumes electricity. While you could run a generator 24 hours a day, it is a horribly inefficient waste of fuel, as well as a surefire way to piss off your neighbors and attract unwanted attention.

Any serious power outage strategy will also include one or more storage batteries, a 12 volt-to-120 volt inverter, and a quality battery charger. You can run your generator in the daytime to power appliances and charge batteries, then shut it down overnight while you quietly run your devices on the stored power in your batteries.

Foundational Information

The electricity that comes out of your wall sockets is 120 volts, alternating current (AC). AC current is easy to transmit long distances, but cannot be stored. AC current is very dangerous if mishandled, resulting in burns, electrocution, and/or death. Conversely, direct current (DC) which is used in phone, laptop and car batteries is able to be safely and easily stored for later use. 12 volt DC current is one of the keys to emergency power.

Let’s define a few electrical terms:

  • Current: This parameter is measured in Volts; think about a mountain stream, the higher the current number, the stronger the current and the more power is transmitted through the current. This is a measure of force, or “push.”
  • Amperes (Amps): This is a measure of quantity of electricity…we’re most familiar with amps because it is usually an overload of amps on an electrical circuit that causes a fuse to blow or a circuit breaker to trip. You know, Mom using her blow dryer while Susie heats up her coffee in the microwave…too much power in use. Batteries are rated in terms of “Amp-hours,” which is an expression of how long the battery can provide a certain quantity of power.
  • Watts: This is the measure of the amount of work that can be done. In general, this is the key measure in determining if appliances can be accommodated in a given electrical circuit. This is a familiar measure for light bulbs and blow dryers. More importantly, it is the measure used to rate the power generating capacity of portable generators and inverters.

AC current can be converted to DC current; we do this every day when we plug in our phone or laptop charger. DC can be converted to AC through the use of an “inverter.” To store power, we use “deep-cycle” batteries which look like car batteries but are specifically designed to efficiently take in and give back DC current. When we need AC current to run a refrigerator or lights, our inverter converts the DC current to AC.

Determining What You Need to Power Up

Like generators, inverters are rated in watts, so you can easily choose the model for your needs. Deep-cycle batteries (also called RV or Marine) are rated in amp-hours. Using the formulas below, you can calculate the size and number of batteries to support your system.

If you can understand a couple of basic formulas, you are set:

Watts=Volts x Amps


All electrical devices are marked with their power requirements, allowing you to make an electricity “budget” and intelligently plan for your needs. For example, my refrigerator requires 5.0 to 6.5 amps when operating. Using the equation above we can determine the number of watts it needs: 6.5 x 120 volts= 780 watts. Here are some common wattage requirements for various appliances:

• Table lamp: 40-100 watts

• Toaster: 800 watts

• Microwave oven: 1500-2000 watts

• George Foreman grill: 800 watts

• Electric skillet: 900 watts

• Cellular phone charger: 24 watts

• Laptop AC adapter: 72-144 watts

• 42” Plasma TV: 286 watts

• Digital cable box: 40 watts

If I expected to run all of the above devices at the same time, I would need to provide up to 5,100 watts of electricity. However, if I planned ahead and was careful not to use high-wattage devices at the same time, I could get away with only half of that capacity. As you might expect, the more watts you need, the more it will cost.

Building a System

So let’s build a simple system based on the above information, assuming that we will run the generator 12 hours a day (7:00 AM to 7:00 PM) and use inverter-provided power the other 12 hours. If we do all of our cooking while the generator is on, we can get along with a smaller inverter and less battery capacity for our nighttime needs. We can also freeze some ice blocks during the day, putting them in the refrigerator compartment at night and turning the fridge and freezer controls down to low at night. As long as the fridge stays closed, it will run minimally at night.

Our system will include a 3,500 Watt-rated generator ($400), a 1,600 Watt inverter ($110), two Sears Diehard Marine batteries with 180 amp-hours capacity ($220), and a Diehard automatic battery charger ($75). This is a solid, basic system that can be upgraded as needed, and will maintain your ability to communicate, cook, store food, and keep alert for emergency notifications. Don’t forget to sock away enough extension cords to reach your appliances.

Your electrical preparedness strategy is crucial to your family’s safety and comfort in a disaster. The good news is that you don’t need to be an engineer or electrician to properly prepare for when the lights go out.

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