YOUR SOLAR POWER SOLUTION
When it comes to power generators for preppers, silent beats quiet. Noise created by an internal combustion engine-powered generator announces that you have power and fuel while most others don’t.
So, along with its independence from the need for fossil fuel, silence is a key reason to consider a solar generator. Having owned both methods of power generation, I write from experience. And if you’re not mechanically or electrically skilled, the following might be particularly informative.
You could buy a turnkey solar generator, but building your own provides additional benefits. Selecting and assembling components provides hands-on maintenance knowledge that demystifies the end product and enables you to get exactly what you want.
There is some technical information you’ll need to familiarize yourself with, but the actual construction of a system is not as challenging as you might have thought.
Of course, if you don’t live in an area that receives abundant sunshine, this might not be a viable option, and you might want to use an internal-combustion or another type of generator.
USAGE DETERMINES SYSTEM REQUIREMENTS
Determining your need for a generator’s power output is fairly straightforward. Make a list of the lights, devices and appliances you use on a regular basis. Note that some appliances, such as refrigerators, require more wattage at start-up than for regular operation.
Take this into account during your assessment. Each device will have a label stating the number of watts it consumes or its voltage and amperage requirements, from which you can determine the wattage.
Add the wattages together to calculate the rating for your generator. You probably don’t run all these items at the same time, so pay attention to those you do use simultaneously and note the sum of the combination with the greatest demand. Your intended use will drive which components to choose, so be conservative when calculating your needs.
You’ll need one kind of solar generator to charge your laptop and quite another to use as whole-house emergency backup power. See the following examples to figure out your electrical power needs.
POWER CONSUMPTION OF COMMON HOUSEHOLD DEVICES
Manufacturers use watts as the standard to specify a conventional or solar generator’s output power rating, as follows:
- 250 watts or fewer: Suitable for small household appliances, personal electronics, battery chargers, televisions, DVD players, computers and small office equipment, and LED lighting. Many devices connect with a 12-volt plug.
- 500 watts: Consider this size for larger household appliances, including large stereos, counter-top kitchen appliances and power tools. Most have two grounded receptacles for powering devices.
- 1,500 watts: Appropriate for most household appliances, larger power tools and incandescent lighting. Some systems are on wheels, thus significantly enhancing their versatility.
- 3,000 watts: Suitable for all household appliances and office equipment. These generators usually have large battery banks and several grounded receptacles.
GLOSSARY OF BASIC ELECTRICAL TERMS
Familiarizing yourself with a few terms will help you understand generator specifications.
AC: Alternating current is an electric current that reverses direction in a circuit at regular intervals. Household receptacles typically supply AC current that reverses direction 60 times per second.
Ampere (amp): A common measure of electrical current in a conductor. One amp is equal to the flow of about 6 billion electrons per second.
DC: Direct current describes the continuous flow of electricity in one direction through a conductor. Batteries and vehicles operate with DC.
Volt: A measure of electric potential. Standard outlets in most American homes are wired to provide 110 to 120 volts. Most electric clothes dryers and stoves and some other equipment require 220 to 240 volts.
Watt: A unit of electrical power. For example, incandescent light bulbs are rated by watts to indicate brightness. You can determine watts by multiplying together voltage and amperage.
Like conventional internal combustion engine-powered generators, solar generators contain components that function as a system. Except for the panels, my system is contained in a rugged polymer case that has wheels to allow it to be located as needed.
Inverter: This device changes DC (direct current) from a photovoltaic panel (12, 24 or 48 volts DC) to AC (alternating current; 120 or 240 volts AC) for powering household appliances and tools. Good inverters are at least 90 percent efficient. More-expensive inverters create true sine wave electricity, while most generators create modified sine wave electricity.
Battery: One or more batteries (12, 24 or 48 volts DC) store and provide power when there is insufficient sunlight for the photovoltaic panel(s) to power an appliance or circuit. Look for a generator that can simultaneously charge the battery while powering a device, tool or appliance. Battery types range from inexpensive lead-acid (automotive type) or no-maintenance AGM (absorbed glass mat) to newer and more-expensive LiFePO4 (lithium-ferro-phosphate).
Besides using photovoltaic (PV) panels to charge a battery, plugging the genera- tor into a 120V AC household receptacle, if available, and using a battery charger comprise another way to charge the battery when the sun isn’t shining. (Note: Do not use conventional chargers for lead-acid batteries with LiFePO4 batteries and vice versa.)
When replacing a battery, determine if it is a regular or deep-cycle type. The former is a standard automotive battery, while the latter is heavy duty (like those used in golf carts and larger U.S. military trucks) and withstands more charge-discharge cycles than a standard battery.
Charge controller: This unit monitors and directs DC voltage from the photo-voltaic panel(s) to charge the battery or power a device or appliance plugged into a generator receptacle. The controller automatically prevents overcharging the battery, which can reduce battery life—or ruin it.
Photovoltaic (PV) panels: This renewable fuel source transforms sunlight into direct current to charge the battery. These are manufactured in a variety of configurations, from small flexible units to large, ground- or roof-mounted panels. More panels equals more power.
Comparison Shopping: When comparing generators and prices, make sure that if you’re looking to buy a complete system, it includes all four components. With solar generator prices ranging from $50 to $10,000 and more, research is essential for making the right choice.
Portability: Do you need to be able to move your system to multiple locations? Do you want to be able to carry it, roll it like carry-on luggage or tow it behind your vehicle? If so, weight and bulk become important considerations.
Receptacles: Options are available to enable the use of automotive-type auxiliary power plugs to power 12- or 24- volt DC devices, standard household plugs to power 120- or 240-volt AC devices, or USB-friendly connectors.
ASSEMBLING THE SYSTEM
Connecting the system elements is simple, because component terminals are marked for identification. If you buy all components from one vendor, a customer service representative will answer your questions and walk you through the steps. Go online to discover and research vendors of solar-generator components and turnkey systems.
Total Solar Technologies
Solar Burrito Blog
Editor’s note: A version of this article first appeared in the June 2017 print issue of American Survival Guide.