Solar Components – A Very Basic Overview
Before you start sketching your solar system, you must first understand the different components. Whether you are interested in an entire-home system, or only powering emergency lighting or a small radio, the principles are the same. The primary components for a solar system are panels, batteries, and a charge controller. The quantity and size of these primary items depends on the size of your system. And with each new item, the cost of the project goes up.
Solar panels come in many different shapes and sizes, and can range from less than 1 watt to over 250 watts per panel. The larger the solar panel, the more current it creates. Current is measured in Amperes or Amps. Solar panels also come in different voltage configurations. The most common are 12 and 24 volt panels. You can use a solar panel to run an individual device, or use it to charge a battery.
Batteries store power. In your vehicle, the alternator charges your battery. In a solar system, the solar panel charges your battery. If you are using more than one battery, it is called a battery bank. For batteries, you need to know how many amp hours are contained in your battery / battery bank, and know the voltage for your system. The more amp hours contained in your battery bank, the more reserve power you will have. The most common type of battery used for alternative energy applications are deep cycle batteries. Additionally, most deep cycle batteries are 2, 6, or 12 volt. Depending how you wire your battery bank, will determine whether you increase voltage or amp hours. If you wire in parallel, you increase amp hours. If you wire in series, you increase voltage.
The charge controller is the heart of the solar system. In a solar setup, the panels are connected to the charge controller, and then the charge controller is connected to your batteries. A charge controller is used to maintain the proper charging voltage of your batteries, by regulating the charge to the batteries and preventing overcharging. There are several types of charge controllers, to include MPPT, PWM, and PWM shunt controllers. A charge controller is designed to handle a certain amount of input amps from your solar panels. Additionally, you must ensure your charge controller matches the voltage of your solar panels and battery bank. If you are using a 12 volt panel and a 12 volt battery bank, then you should have a 12 volt compatible charge controller.
The goal to any solar system is to make sure you can expand it. You can add more solar panels, batteries, and even charge controllers. When designing a system, you must determine how many amps your solar panel or solar array will generate, and ensure that total is less than the charge controller’s maximum input. Let’s say a 100 watt solar panel generates 5.7 amps of power. You have a charge controller that has a maximum of 7 amps input. The 100 watt panel can be used with the 7 amp charge controller. But, if you have two 100 watt solar panels (or 11.4 amps), then the solar array will exceed the maximum 7 amp input of the charge controller. Therefore, you will need another charge controller, or purchase a charge controller that can handle the more than the 11.4 amps.
For more information on wiring 12 volt electrical systems, please read Managing 12 Volts: How to Upgrade, Operate, and Troubleshoot 12 Volt Electrical Systems
Understanding Power Requirements
Now that the basic solar components have been discussed, we will now switch to understanding power requirements. Each electronic device that you use will require a certain amount of power. Your solar panels and battery bank work on DC power. Any 12 volt electronic device can work directly off of your panel / battery bank, think items that you would plug into your car’s cigarette lighter. If you have AC only devices, or something that plugs into a wall, then you will need a power inverter to convert the DC power generated from the panel and battery bank to AC power.
Each device will also have its own power pull. To explain this, let’s analyze the common types of light bulbs currently on the market.
1 x 75 Watt incandescent bulb uses 6.25 amps (Watts/Volts=Amps)
1 x 25 Watt Compact Fluorescent Light (CFL) uses 2.1 Amps
1 x 16 Diode LED light uses .12 Amps
Using the above examples, you can use 18 x 16 diode LEDs for the same power pull as a single CFL light bulb, and 52 x 16 diode LEDs per each incandescent bulb. It makes more sense to use LED lights for solar applications. When purchasing electronic devices that will be used on alternative energy systems, you must identify the device’s power consumption. Similar items can require significantly less power than their counterparts. Efficiency is the key when using off-grid power.
For any alternative energy system, you will need to scale the system to your individual needs. If you need to power a refrigerator, air conditioner, and entertainment center, you will need to have several large solar panels, and a large battery bank. But, if your goals are to only run a few lights and recharge small electronic devices, then your system can be significantly smaller. To put this in perspective RVers that bondock (camping off of the grid for extended periods of time), may have 600-800 watts of solar panels and over 400 amp hours of battery storage. This type of system can be extremely expensive (over $5,000). In contrast, hikers may only carry a small flexible solar panel to charge their portable electronics devices. Some of these portable systems can cost less than $100. While these examples are on the opposite ends of using solar power, it provides a good perspective into how we could use solar power.
If you are developing a system for home or portable usage, you need to understand that this system can be scaled. By adding more components over time, you can grow the amount of reserve power your system provides. Most individuals will start off with one battery, one solar panel, and one charge controller. There is nothing wrong with using this method; in fact this is the method I recommend if you are on a budget. You can easily add another panel one month, a battery the next, and possibly upgrade your charge controller later.
A Small Solar Setup
Since we now have an understanding of the required items, and understand power consumption, let’s create a small solar system. There are two goals for this solar system. The first goal is to demonstrate how to build a small solar solution, at a decent price. Again, there are not many differences between a small portable system and an entire-home system. The second goal is after building this system, you will have a portable solar solution that you can put in your vehicle or leave in your home for emergency use. This system is scaled for short term usage, and can power several LED lights, a fan, or any other small 12 volt device. You can even charge a cell phone, GPS, or AA/AAA batteries. Additionally, you can add more solar panels and another battery to this small system, without having to upgrade the enclosure or charge controller.
By building your own solar system, you can save 2-3 times the amount of money required to purchase an off the shelf solution. This system also has more capability than a hiking solar kit, since it provides reserve power, which means you can continue to recharge batteries and run 12 volt devices even when the solar panels are not generating power. The budget for this system is $150.
What You’ll Need
1 x 10W High Efficiency Solar Panel | $40
1 x 10AH Deep Cycle Battery | $27
1 x 7 Amp Charge Controller | $17
1 x .50 Caliber Ammo Can or similar enclosure | $10
1 x Inline Fuse Holder | $4
1 x 5 Amp Fuse, 1 required but you should also have spares. Do not exceed 10 amp fuse. | $1
2 x 12 Volt Outlet, preferably marine grade with a cover | $10
5 Feet of 16 Gauge Red Primary Wire | $1
5 Feet of 16 Gauge Black Primary Wire | $1
1 Pack of Velcro | $10
Misc. Cable Terminals (Female Quick-Connects, Ring Terminals) - $10
Total Cost: $147
Step 1 – Determine Layout
You can use any enclosure that you want, but this example will use a .50 Caliber Ammo Can. All of the components will fit inside of the ammo can, but the solar panel will not. Additionally, we will use a 12 volt outlet to plug in the solar panel (input), and a separate 12 volt outlet to provide DC power for your devices.
Step 2 – Drill / Cut Holes for 12 Volt Outlets
Using a drill, or other cutting method, cut two holes into the ammo can where the 12 volt outlets will be placed. See images for suggested locations. The 12 volt outlet should fit snug in the hole. Keep in mind that another battery can fit inside this enclosure, so ensure your components do not interfere with the secondary battery.
Step 3 – Mount 12 Volt outlets
Place the 12 volt outlets into the ammo can, and use the nut to tighten into place. You can also use caulk to create a waterproof seal during this step, or wait until the end.
Step 4 – Secure Charge Controller and Power Posts
Using the Velcro, apply one side to the charge controller and power post/s, and one side to the ammo can. Or, you can drill holes into the ammo can, and secure the power posts. I used the Velcro method so that I could use the same wiring harness for different projects. Yes, you can utilize these components for larger panels. Do not exceed 100 watts of solar panels. Additionally, the example shows two separate power posts, but the recommended product is a one piece dual-power post. I think the one piece dual power post is the better purchase, but you can use either.
Step 5 – Install Terminals to the Charge Controller Solar Panel Cables
Find the two cables that will be connected to the solar panel. If looking at this specific charge controller, they are located on the right. Apply two female quick-disconnects to the cables that will be connected to the 12 Volt outlet plug.
Step 6 – Install Terminals to Charge Controller Battery Cables
Find the two cables that are to be connected to the battery. Instead of wiring directly to the battery, we will wire these cables to the power posts. Install two round terminals that are large enough for the power post bolts.
Step 7 – Make Cable for 12 Volt Power Outlet
Using 1’ of both red and black primary wire, create a cable. One end should have a female quick-disconnect terminal that will plug into the 12 volt outlet plug. The other end will have a round terminal which will be secured to the power post.
Step 8 – Make Battery Cable
The battery cable will consist of a fuse holder connected to the positive terminal and the positive power post. On the inline fuse holder end, use a female quick-disconnect terminal to attach to your battery terminal. On the other end, use a round terminal that will attach to the power post. For the negative terminal, use the same terminal method.
Step 9 – Wire Solar Panel to a 12 Volt Male Plug
For this system, we wanted to ensure that our wires would be self-contained (we did not want wires that could be damaged by closing the lid). You will have several options for wiring your solar panel to a 12 volt male adapter. I use a two pole quick disconnect plug with a 12 Volt male two pole disconnect end. However, if you have a spare 12 volt male plug lying around, you can wire that directly to a solar panel. To reduce costs, we will use the later method. Simply splice your cables, and connect positive to positive, negative to negative.
Step 10 – Mount Battery in Ammo Can
Use Velcro strips to secure the battery in the ammo can. Velcro should be placed on the bottom, front, and side of the ammo can and battery.
Step 11 – Wire the System
11a – Connect the Charge Controller – Solar Panel cables to the rear 12 volt outlet.
11b – Connect the Charge Controller – Battery cables to the power posts (positive to positive, negative to negative)
11c – Connect the 12 Volt power outlet to the power posts (positive to positive, negative to negative)
11d – Connect the battery harness to the power posts.
11e – Connect the battery harness to the battery terminals
11f – Insert your fuse
Step 12 – Plug in Solar Panel
Plug in your solar panel to the rear 12 volt outlet. Your system is now operational. Use a voltage meter to ensure everything is wired correctly.
What Can This System Power?
Lights – You can make your own, or purchase small 12 volt light sets. The Diamond Group has two great options, a single pancake LED light (draws .12 amps) or a dual pancake LED light (draws .22 amps). This system can power a single pancake light for over 75 hours on a single charge.
Small Electronics (cell phones, GPS) – All you will need is the provided 12 volt accessory plug, or purchase a 12 volt USB plug. We recommend the 5 in 1 plus USB 12 volt socket.
Fans – You can use any 12 volt compatible fan. We like the O2 Cool 5” Fans, but you will have to make a 12 volt plug adapter. Or you can purchase the larger fan, which comes with the 12 volt adapter and battery pack.
Battery Charger – You can use a 12 volt battery charger with this setup.
The neat thing about these add-on components is that they can also be used in your vehicle or with a larger 12 volt solar setup. The point here; invest in 12 volt devices, so that you can use them with various systems.
This system is designed to charge electronic devices or run small 12 volt devices. Remember, this system is that it is not all that different than a much larger solar system. All that will change is the number of components, incorporating a power inverter, and additional wiring. Solar is not that difficult to understand. Please let us know what you think about this solar solution. Additionally, please check back with us. We will release a few more components for this system and videos discussing solar solutions in the near future. Be Prepared. Get Connected.