Understanding electric fundamentals, electrical basics, terms, definitions and concepts.
Electricity is one of our most widely used forms of energy. It wakes us up in the morning, lights up our homes, cooks our food, powers our computers, tv sets and other appliances. It gets us to work, makes our cup of coffee and even let's us communicate with other people all over the world all day long.
If you want to break it down to electrical basics, electricity is essentially the flow of electrical current, power or charge. It occurs both naturally in our environment in the form of lightening and is also produced from the conversion of other "primary" sources of energy, such as coal, nuclear or solar energy.
Electrical fundamentals refers to the electrical basics, terms and concepts you should understand before taking on any electrical project. It's not hard to get a good understanding of the electrical fundamentals, just read the rest of this page and you should be a lot more up to speed.
Understanding electrical fundamentals and electrical basics starts with understanding that all electrical equipment is rated in watts, volts and amps.
In order for any electric system (including a solar system) to be able to power appliances it must be able to produce the same (or more) watts, volts and amps as is required by any given appliance or by your power usage needs.
Electrical Basics (Watts)
Watts represent the amount of power produced or used. Think of it sort of like your "power reserve".
I like to picture watts like a bucket of water. The bucket is the power container (solar system) and the water represents the amount of power you have available to use.
The more watts your system has the more power you can use.
So what are watts? Watts are the amount of power (water) in your system (bucket).
Electrical Basics (Volts)
Volts represent the pressure of electrical flow (the push). Think of it sort of like the "water pressure" in a pipe.
The more volts your system has the bigger the appliances you can power.
So what are volts? Volts are the amount of push (water pressure) used in your wire (pipe).
Amps represent the intensity (amount & speed) of current and thus determine the size of the wire needed. This in turn directly affects the energy production / charge speed. Sticking with our previous example, think of amps sort of like the "pipe size".
The more amps your system has, the bigger the "pipe" (wire) used and the faster you can make/store energy.
So what are amps? Amps are the intensity (speed) of the current and thus determine how fast you make power (use water) and the wire size (pipe size) needed.
To figure out how many watts an appliance, a solar panel, a solar cell, a battery bank or an entire solar system has, you just multiply the Volts x Amps.
Volts x Amps = Watts
Electrical Fundamentals (Watt Hours)
Watt / Kilowatt hours is the measurement used by your electric company to charge you on your bill. It represents the number of watts consumed multiplied by the number of hours you consume it for. One watt hour is equal to consuming one watt of power per one hour.
Watt hours = # of watts consumed x # of hours
Watt hours is just like another way of saying "watts used/made per hour".
A kilowatt is equal to 1000 watts. It's just another way of saying 1000 watts, only it appears neater and is less bulky looking on your utility bill. So one kilowatt hour is equal to consuming 1000 watts of power for one hour.
To calculate the amount of watts/kilowatts a specific appliance consumes per hour (and therefore will need your solar system to produce per hour) you need to go around to all of those appliances, get the watt rating off each, multiply each by the number of hours you would normally use that appliance for and add up all the totals. Don't worry, we cover this process in much more detail in Solar System Sizing.
Electrical Fundamentals (Amp Hours)
Another one of the electrical fundamentals you should understand if you're going to be working with solar energy systems is Amp Hours.
Since amps represent the intensity of the current (wire size), then...
Amp hours represent how much electrical current can flow per hour. This value would appear on the battery you use in your solar system.
So if you only have one battery in your solar system and it says 105 amp hours on it, then this means you could charge it to produce 105 total amps during the course of an hour.
Of course you wouldn't use it like this, you would spread the available amp hours out according to your appliance's amp hour rating, but this is just meant to give you an indication of the storage capacity of the battery and how long it takes a battery to discharge.
The more amp hours you have in your battery bank the longer your total power reserve would take to deplete. To learn more about solar batteries and what types of batteries are available for use with pv solar systems click here to go to the All About Solar Batteries section of our website.
Electrical Fundamentals (Current)
The two types of current are:
DC only flows in one direction and it is common in battery powered devices such as flashlights, mobile phones, pdas and TV remotes. It is also what is produced by solar panels and stored in your battery bank.
AC alternates the flow of the current at regular intervals and is commonly used for bigger devices like household appliances.
In other words, DC electricity is what solar panels create which is then converted to AC electricity using a power inverter (so you can use it for household appliances).
Some appliances can run on DC electricity such as DC powered tvs, fridges and others designed for use in campers, rvs and in the outdoors, however the appliances in your home will almost certainly always run on AC (alternating current).
Electrical Fundamentals (Wiring)
Series wiring is when you connect your panels or batteries or any electric circuit, positive to negative, negative to positive, etc and it is used to increase the overall volts.
Parallel wiring is when you connect your panels or batteries or any electric circuit, positive to positive, negative to negative, etc and it is used to increase the overall amps.
Here is an example of the same two solar panels wired in both series and in parallel. One has higher Volts (so you can power bigger appliances) and the other has higher Amps (so you can charge your batteries faster).
Notice how the two panels wired in series have higher voltage (power) and how the two panels wired in parallel have higher amps (intensity / charge speed).
Choosing whether you use series or parallel wiring is just a matter of knowing whether you want to increase the overall volts or amps -based on your needs.
The last wiring type is a combination of series and parallel wiring. This is accomplished by wiring two or more groups of solar panels (or batteries) together in series and then connecting those individual groups together in parallel. This type of wiring is used to create a better over all balance of volts and amps in your solar system or battery bank.
Here is an example of four panels wired in a combination of series and parallel.
Notice how this series and parallel wiring combination maintains a good balance of both volts (power) and amps (intensity / charge speed).
Therefore, you would typically use the series and parallel wiring combination if you wanted to have more power and more load capability at the same time.
The goal of this page is to give you a brief understanding of electrical fundamentals, basics & concepts, and how they apply to solar power.
By now you should be able to answer the questions:
What are watts? What are volts? What are amps? What are watt hours? What are amp hours? What is DC & AC current? What is series wiring? What is parallel wiring?
And you should kind of understand how these electrical fundamentals apply to solar power. Remember the "water in the pipe" example?
If you're at all confused by the electrical fundamentals, don't worry, we get into more detail on this subject later in Solar Panel Wiring. We even make it extra easy for you by showing you the exact panel / battery wiring combination for multiple sized systems - so you can copy them.
Click here to go back to the Solar System Sizing section in the exact spot you left off (or just click your browser's back button).