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Module 1: Solar and Electricity Basics (Volts, Amps, Watts, AC, DC)

Welcome to the first module in our course. Before we start talking about sizing solar panels, batteries, inverters, and other components, it’s important to cover the basic concepts and terms.

It may seem like a waste of time, but understanding these fundamentals will make everything else much easier. Not only will it help you understand what your equipment is doing, it will help you make informed buying decisions down the line.

Understanding Volts, Amps, and Watts

Electricity can be a bit confusing, so we’re going to break things down with a simple analogy. Imagine for the purpose of this lesson that you have a faucet connected to a garden hose that is filling a bucket with water.

If you'd like to keep a copy of this material for future reference, remember to download the full course as a PDF. That way you can access the guide offline and even print your own copy.

Volts (V) - The Pressure: 

Think of volts as the water pressure coming out of the faucet. Like water pressure, your voltage is what pushes the electricity through the circuits in your system. 

In most North American homes, you’ll either have:

• 120V outlets (standard household plugs)
• 240V circuits (which is just two strands of 120V used for demanding appliances, like dryers, ovens, and things like EV chargers). 

The higher voltage means electricity can move through the wires easier, just like high water pressure pushing the water through a hose at a faster rate.

Amps (A) - The Flow Rate: 

Think of Amps like the width of the hose. A thin hose allows less water (electricity) to flow through, while a wider hose allows more. 

Amps are a measurement of the current, or the amount of electricity flowing through the wires at any given moment. 

Higher amps = more electrical current is flowing.

Watts (W) - The Power: 

Finally, watts are what come out of the hose, or the actual power output.

Just like water flowing from a hose into a bucket, watts flow through the system to power your appliances, devices, or charge your battery. In other words, this is the actual power you get. 

Watts is a number you’ll see a lot when shopping for solar equipment and portable power stations, so it’s really important to understand what watts are.

Calculating Watts 

Watts can also be calculated by multiplying volts by amps (Volts x Amps = Watts). 

For example, let’s say you have a vacuum that operates at 120V and draws 15A—it would use 1,800W: 120 Volts x 15 Amps = 1,800 Watts.  

This formula is one of the most important in all of solar power, and it’s something you’ll likely end up using often. It can help you with sizing solar panels, batteries, inverters, and even the appliances you plan on running with your solar power system.

We’ll go into this in more detail in some of the upcoming modules, but understanding this formula and what these terms mean will put you ahead of most first-time solar equipment buyers.

⚡ Solar Lab Tip: Voltage vs Amperage in Real Life

Higher voltage systems (like 48V batteries) can move the same amount of power with fewer amps. That means less heat, thinner wires, and better efficiency, which is why a lot of modern solar systems are shifting towards higher voltages.

AC Power vs. DC Power 

Now, let's talk about the different types of current: AC Power (Alternating Current) and DC Power (Direct Current). 

This is where a lot of people really get thrown off, but it’s actually not that complicated when you break it down.

DC (Direct Current): 

With DC power, electricity flows in one direction, much like water through a hose. 

This is the type of current generated by solar panels. It’s also what will be stored inside your solar batteries or solar power station’s internal battery.

You’ll also find that DC power is used for low-voltage applications like car batteries, which is why you may notice that your vehicle’s auxiliary power outlet, or cigarette lighter port, is often called a 12V DC Port.

AC (Alternating Current): 

AC power is what you get from the power grid, and it’s also the type of current you’ll pull when you plug anything into a standard outlet in your home. 

Instead of flowing in one direction, AC current alternates back and forth. You can picture it like rolling waves in the ocean.

Since most of your devices and appliances (fridge, microwave, tools) require AC power, almost every solar power system, or portable solar power station, will feature a power inverter that will turn the DC power stored in your batteries into AC power.

Power Inverters 

Speaking of power inverters, they are often seen as one of the most important components in any solar power system. 

The inverter’s job is to convert the DC power that is generated by your solar panels and stored inside your solar batteries into the AC power that your home appliances and portable devices can actually use.

Some inverters can also convert AC to DC, but in most solar setups, you’ll be converting DC to AC.

Power Storage: Watt-Hours and Kilowatt-Hours

Power storage tells you how much energy a battery can hold. With solar equipment, it’s usually referred to as the “battery capacity” or “storage capacity”. 

Basically, it’s the total amount of energy your batteries are capable of storing when they are fully charged.

Watt-Hours (Wh):

Power storage is usually measured in watt-hours (Wh). For example, if you have batteries with a combined capacity of 6,000Wh, you have 6,000 watt-hours of total storage capacity.

With perfect efficiency, that 6,000Wh battery should be able to run a 1,000W device for 6 hours, or a 100W device for 60 hours.

Kilowatt-Hours (kWh):

When dealing with larger solar batteries and solar power systems, things are usually measured in kilowatt-hours (kWh). 

A kilowatt-hour is just 1,000 watt-hours. It’s also a way to measure energy consumption over time. 

For example, if your home uses 30 kilowatt-hours of electricity per day, it’s just a shorthand for 30,000 watt-hours of energy (30kWh = 30,000Wh).

⚡Solar Lab Tip: Battery Storage ≠ Power Output

A battery with a huge kWh rating doesn’t necessarily mean it can run big appliances. Storage (Wh / kWh) and output power (W) are different specs, and both matter. 

Your power inverter will determine your output power in watts, while your battery will decide your storage capacity in Wh or kWh.

Other Useful Solar Terminology

We’ll cover most of this in more depth during the upcoming modules, but there are a few other solar terms that are worth familiarizing yourself with: 

PV (Photovoltaic):

This term is pretty much synonymous with solar power. Photovoltaic, or PV for short, is just a more technical term for solar electricity. It’s the technology that converts sunlight into electricity. 

When you see "PV input" on a device, it’s referring to the solar input, or where you would connect your solar panels to your system or solar generator. 

       PV Panels = Solar Panels

       PV Input = Solar Input

You’ll also see a wattage rating listed alongside your PV or solar input. This just refers to the maximum amount of solar power the inverter, battery, or power station can accept.

Solar Array: 

Your solar array is the total collection of solar panels you have connected to your system. 

If you had four 100W solar panels, you would have a 400W solar array. If you had twelve 200W solar panels, your solar array would be 2,400W.

It’s just a quick way to describe the total power generating potential of all of your solar panels combined.

Putting It All Together 

Now that you are familiar with the different terms and the symbols that represent them, let’s quickly revisit our analogy to tie everything together. 

When you turn on the faucet (volts), water flows through the hose (amps) and fills the bucket (watts). If you have a bigger hose (more amps), the bucket fills faster (more watts).

Your solar panels generate DC electricity, which flows like water in one direction. To power your home appliances and other electrical loads, an inverter converts this DC power to AC power. This creates the alternating waves of electricity your appliances and devices need (unless you have DC appliances).

When it comes to solar power, watts tend to be your key measurement. Everything from solar panels to inverters and batteries will be rated in watts (W) or watt-hours (Wh). 

To figure out how much power your devices need, you can use the simple formula: 

       Volts x Amps = Watts 

Why This Stuff Matters

This lesson might seem pretty basic, but now you understand the basics of solar power and electricity.

Understanding volts, amps, watts, AC and DC power, and basic power storage terms will make every future solar decision easier. From choosing a power station to sizing components, you now have the fundamental knowledge to make smarter buying decisions and avoid being upsold on stuff you don’t need. 

Remember, you can download the PDF if you want to access any of this information offline.

Up Next: Module 2 - Sizing Batteries for Solar Power Systems

In the next lesson, we’ll put this solar terminology to work by explaining how you can correctly size batteries for your solar power system. This will also help you choose a power station with the correct battery capacity for your needs.