Estimated reading time: 15 minutes
Solar generators function very much like gas powered generators with some fundamental differences and some distinct advantages. The obvious advantage is that a solar generator is powered by the sun rather than gasoline. That means there are no exhaust fumes like carbon monoxide, allowing a solar generator to be both stored and used indoors if they are equipped with the proper batteries.
Another advantage is that the power from the sun is free as opposed to the continuously rising cost of gasoline. Solar generators are also very quiet compared to a gas generator but all of these advantages come with a price.
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Solar Generators are a Bit Complicated
There are numerous parts and pieces to a solar generator. These include the solar panels, a charge controller to manage charge delivered to the batteries, batteries to store power, and a power inverter to convert DC power to AC. The good news is that most solar generators have many of these components contained in a case that can sometimes be carried or in larger models, wheeled around.
There are also fixed solar generators, sometimes hooked up to an additional battery bank for long-term, large whole house solar power generation. One thing that’s obviously critical are the solar panels powering the generator.
Some are free-standing, allowing for a portable setup, while others are attached to the roof of a house or outbuilding. We’ll cover whole-house solar generators in addition to solar generators scaled down for emergency or portable, part-time use.
The Language of Solar Power Generation
As we go though some of the details of solar power generation we’ll come across some terms and words that may be new to you. If that’s the case, here’s a primer on the language of solar power.
Most of this has to do with electricity and batteries, but there are some terms related to solar equipment, panels and overall system performance that are important to know when picking the ideal system for your needs. Some of the lower priced solar generators you come across may offer hidden compromises that will affect the lifetime of the generator and its performance, so these key terms are worth knowing.
W – “Watt”
A watt is a measure of electromagnetic energy. It is used to quantify the rate of energy transfer
kW – “Kilowatt”
A kilowatt is 1,000 watts.
kWh – “kilowatt hour”
The amount of watts that an average house will use gets high, so we’re going to measure in kilowatts or kW which is 1,000 watts. The amount of watts you need in an hour is referred to as a kilowatt hour or kWh.
“Amp”
An amp is a measure of the flow rate of electricity through a wire or cable into an electrical system. The higher the amp number, the faster the rate of electrical “flow.”
AH – “Amp Hours”
A measure of the total number of amps that travel through and into an electrical system in one hour.
Volt
A volt is the unit of measure of the electrical force or pressure which causes an electric current to flow in a circuit.
DC – “Direct Current”
DC is a low voltage form of electricity that is initially generated by solar panels and stored in batteries. It flows in one direction and is typically used in electronics.
AC – “Alternating Current”
AC is a high voltage form of electricity that flows back and forth and typically powers lighting, appliances, and other electrical items.
“Inverter”
In a solar generator, an inverter converts the DC to AC to power which is needed for most household electrical devices and appliances.
IE – “Inverter Efficiency”
A very important measure identified as a percentage. It ranges from 70% to 90%. All inverters lose some power as DC is converted to AC. Look for an inverter with an efficiency rating of 90%. If the manufacturer doesn’t indicate inverter efficiency, it may mean it has a lower percentage.
PSW – “Pure Sine Wave”
A pure sine wave is what we receive from a standard electric outlet delivered by the grid. A pure sine wave is a steady, continuous wave that provides a smooth, periodic oscillation or electrical flow. Pure sine wave inverters are at the top of the list of functionality, with the ability to run any and all equipment designed to work on a pure sign wave.
MSW – “Modified Sine Wave”
A modified sine wave does not deliver a consistent flow of electricity. It appears in cheaper, low-end inverters. All of our appliances and electronics are designed to operate with a pure sine wave. If you use a modified sine wave inverter, you will end up using almost double the amount of wattage to power that appliance and eventually it will overheat. Look for a pure sine wave inverter.
Voltage Regulator
A solar charge controller (frequently called a voltage regulator) is similar to a regular battery charger. It regulates the current flowing from the solar panel into the battery bank to avoid overcharging the batteries. This may also be referred to as the “control panel” on your solar generator.
IDP – “Idle Power Consumption”
Whenever you have your generator turned on, it will consume power, whether you are using it or not. This is the idle power consumption.
SD – “Self Discharge”
Self-discharge of lithium-ion solar batteries is a normal chemical phenomenon, which refers to the loss of charge of a lithium battery over time when it is not connected to any load. The speed of self-discharge determines the percentage of the original stored power (capacity) that is still available after storage.
Power Save
The power save on a solar generator is similar to the automatic shut-down or sleep feature on a computer that saves power when the device is idle and not in use.
DoD – “Depth of Discharge”
A battery's depth of discharge (DoD) indicates the percentage of the battery that has been discharged relative to the overall capacity of the battery. It’s very important because a deeply discharged battery will take longer to recharge.
“Cycles”
The number of times a battery can be recharged before it must be replaced. Always look for this measure.
MIE “Maximum Inverter Efficiency”
Maximum inverter efficiency is usually 90% or better for good inverters. And though this gives you an idea of how much power you lose, it is not really that useful, because your inverter will probably never get this efficiency (only at a very specific load).
You should increase the size of your batteries and solar by at least 10% for a 90% maximum efficiency inverter, or 20% for an 80% maximum efficiency inverter.
LCOS – “Levelized cost of storage”
The LCOS is the cost of kWh (or MWh) of electricity discharged from a storage device when accounting for all costs incurred and energy produced throughout the lifetime of the device. You may come across this acronym as a marketing term on more expensive solar generators.
“Lead-Acid Battery”
A lead acid battery uses the chemical reaction between lead and sulfuric acid to generate electricity. They’re the most inexpensive battery option for a solar generator, but they require maintenance and venting. Their primary benefit is that they can be recharged across a range of temperatures.
AGM – “Absorbent Glass Mat”
Absorbed glass mat batteries or AGM batteries, became popular in the 1980s. They were used to power motorcycles, military, aircraft, and submarines, but now you can find them in everyday cars and trucks.
AGM batteries are a maintenance-free alternative to traditional flooded lead-acid batteries. They are designed to provide powerful bursts of starting amps and run electronics for a longer period of time.
“Lithium-Ion”
The majority of new home energy storage technologies use some form of lithium-ion chemical composition. Lithium-ion batteries are lighter and more compact than lead acid batteries and do not require venting.
They also have a higher DoD and longer lifespan when compared to lead acid batteries. However, lithium-ion batteries are more expensive than their lead acid counterparts and do not charge well in temperatures below freezing, which is why they are usually stored and recharged indoors.
“Lithium Iron Phosphate”
The most expensive battery type. They are safe, lightweight, have the longest life span, require no maintenance, and have improved discharge and charge efficiency.
“Solar PV Input”
PV stands for photovoltaic. It’s the process of a solar panel generating electricity in watts. Solar panels are rated by these watt-generation capabilities. For example, a 100 watt PV panel generates 100 watts of power in full sun (peak sun-hours).
“Surge Maximum”
Some appliances and equipment require more upfront wattage to begin running. Well pumps and sump pumps are a good example. They may run at a constant cycle at 1,000 watts but could require a 3,000 watt surge of power to get started.
Remember to find the surge maximum for any appliance you plan to run on a solar generator and make sure the solar generator you buy can accommodate that surge.
That’s a lot to remember, but it can help you to buy the right generator for your needs. To keep it simple, just remember, “You get what you pay for,” so don’t skimp on price if you’re planning to use your solar generator on a regular basis over the long-term.
How effective and reliable any solar generator works out to be is dependent on some factors driven by both the equipment and you location on the planet. We’ll start simply with location and then dive into some of the details about the equipment.
The Sunlight Question
Here’s a map of the world identifying average daily hours of sunlight:
If you think about where you live, you can start to get an idea of average hours of sunlight per day. Australia and the southwest parts of North America appear to be ideal locations for solar, while Ireland and the U.K. and parts of China would present some distinct solar challenges.
But just because you don’t live in an ideal area for daily sunlight doesn’t mean that a solar generator is out of the question. A lot depends on how and why you plan to use it, and how you can design it to compensate for varying levels of sunlight.
A Critical Success Factor: Peak Sun
“Peak sun-hours” are not the same as “hours of daylight”. Most of the United States averages between 3 and 5 peak sun-hours, though many areas may experience less during the winter and more during the summer.
Knowing the yearly and seasonal average peak sun-hours in your area is a helpful tool for calculating the correct amount of solar panels needed for a system.
Is a Solar Generator Right for You?
There are some basic questions you need to answer to know if a solar generator is a viable solution to your power needs. Any generator, whether it's gas powered or solar powered, can only do so much.
You need to assess what you’re powering, when you will use it, where you live, why you need any kind of generator, and how you can buy or design the right system or generator.
- Are you using it to power a few lights and appliances like a refrigerator as an emergency backup for a temporary power outage?
- Are you using it full-time to power specific lights and tools in an outbuilding like a barn, shed or chicken coop?
- Are you using it on a regular basis as a supplement to your on-grid power usage to reduce your electric bill?
- Are you using it as your only source of power for a small off-grid cabin?
- Are you planning to use it as a permanent solution for your whole-house electrical needs?
Each of these scenarios will require a different type and size of solar generator, and in more demanding instances like whole-house power generation, it will require additional battery storage and an increased number of solar panels.
For some, a whole-house solution requires an entire solar power system installation but a large solar generator with additional solar panels and batteries for storage could be at least an emergency solution.
Steps to Choosing the Right Solar Generator
√ Calculate Your Daily Power Needs In Watts
There are a number of ways to determine kilowatts, but a lot depends on what you intend to power. If you’re planning to power your whole house, you could simply look at your electric bill and it will tell you how many kilowatts you used for that month.
Look at a year’s worth of bills and total the kilowatt hours and divide by 365, and you’ll get your average daily usage from that year.
The U.S. Energy Information Administration (EIA) indicates the average household consumes 10,500+ kWh of electricity per year. But few people use a solar generator for whole house power.
The most direct way to measure power needs is to determine which lights, electronics, and appliances you plan to power with your solar generator and determine the amount of watts they use. This includes small and large appliances, air conditioning units, lights, televisions, and water heaters. The wattage of most electronics and appliances are printed on the back of the equipment or with light bulbs on the top or side of the bulb.
You then need to calculate how long that item will require power measured in hours or fractions of an hour. A toaster may use 600 watts, but we rarely use a toaster more than a minute at a time.
After you’ve determined the wattage for each item you plan to power, you need to determine how much you will use that item on a daily basis.
You do this by adding up the number of kilowatt hours (or fractional kilowatt hours) for each item. EIA reports that the average American household uses 30 kWh per day. That’s for a whole-house, and ideally your total for specific priority appliances and lights will be less.
The reason this daily kWh number is so important is that it will guide many decisions you will have to make with regards to the output and capabilities of your solar generator. This will affect not only the number of solar panels you will need but the amount and capacity of your battery or batteries.
Solar generators are priced and sold based on their kWh output. Smaller solar generators deliver 1 to 2 kWh of output while larger models deliver 6 to 12 kWh of output. If you want to increase the output you have the option of adding more batteries but you will probably need to add additional solar panels as well.
√ Understand Solar Generator Batteries
At the heart of any solar system, including solar generators, is a battery or bank of batteries designed to hold the solar power captured from the sun. There are various types of batteries for solar generators and some are vastly superior to others.
What you’ll find is that the most expensive batteries are the best for a variety of reasons. In this case, the best is a lithium Iron Phosphate battery. Lithium Ion is a close second. AGM lead acid batteries are third and the least expensive but require maintenance and venting.
√ Determine How Many Solar Panels You’ll Need
This is determined by your calculation of your total wattage needs on an average day. It’s also important to consider the amount of peak sun you receive.
We’re about to recommend some solar generator kits that come with the proper amount of solar panels, but on average it’s safe to assume you will need at least 10% more solar generating capability to keep the battery bank charged in your solar generator. If you find you run short, add more panels.
√ Choosing The Right Generator
Before we cover the roof with solar panels, we need to identify the size and type of solar generator you need. Most are portable and can be moved from room to room or even packed and taken on the road. Larger models are fixed in place either outdoors or indoors.
One thing to watch is whether or not your solar generator comes with solar panels. Some don’t. It’s best to buy the complete kit because they will provide the proper amount of solar panels with the correct PV output for your generator and its batteries.
Here are some popular models across a range of outputs:
EF ECOFLOW Solar Generator DELTA Max (2000) 2.4kW
This solar generator comes with 4 portable solar panels, and the generator itself can be easily transported from room to room or taken on the road. It provides 2400 watts of power and a surge maximum of 5000 watts.
This is a good emergency solar generator or for any road trip whether you’re camping or bugging out. It could run the power in a small outbuilding or keep critical things running in the house like lights and a refrigerator.
HYSOLIS 6kW
This solar generator has the potential to power a whole house depending on the number of appliances. It’s also expandable with the addition of batteries and solar panels. It runs at 6,000 watts and comes with 18 solar panels. It does not include batteries, which you will have to buy separately, although some people prefer that option.
GOWE 8kW
Whole house solar generator kit. Includes 8 AGM lead-acid batteries. The kit also includes 16 – 150 watt solar panels plus inverter and charger.
Do Some Research
The generator kits we highlighted are only an example of some available options. Do some research and if you need more information, contact any manufacturer and ask questions. A solar generator is a big investment, and you want to get it right the first time.
The good news is that most kits are expandable, but check into that as well. In a time when so much is uncertain, it’s comforting to know you can at least rely on the sun rising every morning.
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