Solar Power: The Ultimate Guide to Solar Power Energy and Lower Bills: (Off Grid Solar Power Systems, Home Solar Power System) - Mark Prentice, James Bickel (2016)

Book 2. Proven Methods To Build Your Own Solar Power System That You Can Afford

Chapter 1. A few things to Understand before You get Started

How Does Solar Power Work?

Originating from the Greek word for light, these “photovoltaic cells” that are involved in the process of creating solar energy are the best light collectors known to man. It is the silicon based alloys within the traditional solar panel that makes it so good at absorbing solar radiation.

Photovoltaic cells are arranged on the atomic level with one atom of silicon broken down into 14 separate electrons that form a series of shells, which in turn is what constitutes the “crystalline silicon molecule” that is necessary in order to collect sunlight so efficiently. (You still with me?)

I know that these are all technical terms that many of you may not be familiar with, but all you really need to know is that it is this silicon surface that absorbs photons of sunlight which has an instantaneous reaction to the cell’s atoms that transfers energy into electricity.

The only limitation that this solar absorption has is that direct sunlight isn’t always available to us. During extended periods of night or cloud cover, your solar collection is of course going to be quite a bit less than what a full brightly lit sunny day can offer.

Battery Basics for your Solar Power System

This brings us to the next great point about solar energy. Because in order to compensate for this time spent without direct sunlight you will need to be able to store the energy you get from the sun into batteries that can be stashed away until the day you need them.

The kind of batteries that you need to be able to do this are called, “Deep Cycle” batteries which are built to be able to directly store energy in this fashion.

Regular batteries like car batteries just aren’t capable of storing that much energy and if you tired to use them for this purpose you most likely would just end up ruining your battery.

Because batteries for cars were really only meant to work in short bursts of power aimed at starting the vehicle, and after that, it is your car’s alternator that really supplies the juice to your car’s electric systems.

Deep Cycle batteries on the other hand benefit from their ability to be filled up completely with energy, storing it all up until you wish to discharge it back into your apparatus.

Most of these types of batteries can discharge as much as 80% of their contents, but it is recommended not to discharge more than 75%. The reason for this is to prevent your batteries charge from becoming too weak—because as anyone whose ever had an iPhone no doubt knows—as soon as a battery dips below 25% it’s not long before it becomes as dead as a doornail. So as a general rule, try to maintain at least a 25% charge on the battery at all times.

Now that this basic concept of the Deep Cycled battery has been established, let’s explore the different types of Deep Cycled Batteries that are currently on the market.

The most common are the “flooded batteries”, second to this are the “gel batteries”, these are then followed by “lead batteries” and Absorbed Glass Mat (AGM) batteries. Flooded batteries are popular and quite ubiquitous due to their cheaper price and their usually fairly tough constitution.

The biggest problem with this battery when it comes to solar power though, is the fact that it must be kept outdoors. You see, the water that floods into these batteries (hence the name flooded battery) will periodically release a specific chemical agent into the air as a byproduct.

In small quantities this gas is harmless, but when you keep flooded batteries inside with closed windows for a prolonged period of time, just like being closed in near exhaust from a car, this trapped gas could eventually prove to be lethal.

So just remember, if you do use flooded batteries you must use them outside. But having to keep the battery outside can present a whole new set of problems for you, because when the weather is particularly cold or windy, leaving that battery out in the backyard could be detrimental.

Because just as anyone who has went outside to start a car in the winter can contend, cold weather does kill batteries! The same can be said for flooded batteries as well.

Since I live in the Northern United States, it is for this reason that I steer clear of flooded batteries altogether and opt for more easily storable gel batteries or even AGM batteries. But do your research—because in the end its your call—and only you can decide this vital foundation on which a solar power system is built.

But as important as they are, batteries are by no means the end of the conversation. Because solar energy can not be utilized directly from a battery, first it must go through a technological little middle man known as an “inverter”.

The Importance of Inverters

Inverter’s running on optimal capacity should be able to reach up to 120 volts of AC (Alternating Current) for each 12 volts of DC (Direct Current) that it receives from the battery.

You should be able to plug your battery right into a volt socket right on the side of your inverter. And besides this design, there is another kind of inverter called a “grid tie inverter” that actually uses your local electric grid as its storage bin.

That’s right, instead of sucking power out of the grid, this type of inverter allows you to send it right back to them! Any extra power you have can be stored up right back into the grid system.

You can then actually sell this energy to your local utility company. Amazingly, this little DIY has you not only saving money, but also turning a profit, all because of solar power. After you get your inverter and batteries taken care of the next thing that you are going to want to look into is finding a good generator.

Running a Generator as Backup

Getting a generator may seem like it is somehow defeating the whole purpose of building a solar power system in the first place, but hear me out. Even though you may get most of your power from solar energy, you still need to have a backup plan just in case your system temporarily fails, or just in case you run into a brief cloudy spell and need to temporarily give your drained battery a break.

A quick emergency charge on your generator will at least keep your solar power system from falling apart.

Just be careful. And if you do have to pick up a charge from your battery, don’t leave it connected for your battery for too long. Batteries can get maxed out very fast when being juiced up direct on a generator.

To avoid over charging never charge your battery more than 95% of its capacity, by all means a battery charged up to 95% is more than enough power and the sun can always charge it up the rest of the way. These are just a few things for you to take into consideration and understand before you get started on your own solar power system.