Solar energy is regarded as a genuinely renewable and eco-friendly form of energy resource available on Earth. Nowadays, people are making the most out of this resource, which is particularly crucial in remote areas where electrical transmission is limited. It’s especially suitable for regions with prolonged sun exposure during the daytime, as it can significantly reduce electricity bills.
We’ll show you how to build a DIY system for charging USB-powered DC electronic devices using solar energy. We aim to explain and demonstrate the concept using minimal components and a simple design.
Understanding Solar Power
Solar poweris the conversion of energy from the sunlight into a usable and efficient source of power.Solar panels and generatorsare used to convert light energy into electrical energy. Solar panels vary in size, ranging from a few square inches to large ones used on residential rooftops. You can also interconnect larger panels across large fields to generate electrical energy for use on a commercial scale.
There are multiple ways to harness solar energy. The most common is a solar photovoltaic (PV) system that converts the sun’s rays into electric current. Aside from using a photovoltaic system to generate electric current, people also use solar thermal energy or concentrating solar power to heat indoor spaces or fluids. you may also install solar hot water systems.
Selecting the Right Components
Our main objective is to use solar energy from sunlight in order to obtain the current required to charge USB-powered devices. You will also require a battery to store charge in the case of bad weather and during sunset. Furthermore, the battery also ensures a continuous supply of the specific current required for charging electronic devices.
For this DIY project, you will require the following components:
Step 1: Block Diagram
The following diagram shows the assembly required to obtain, control, and effectively utilize the power produced by solar panels.
Connect all the devices—such as the generation unit (solar panel), storage unit (battery), and load—to the solar charge controller. This controller will monitor the inflow current, output load current, and charging voltage.
Step 2: Connect the Solar Panel
We are using solar plates (150W) in a parallel configuration to increase the charging current of the battery. You can use fewer or more panels and power capacity as per load requirement. For the parallel combination, connect the positive terminals of all the solar panels together through a wire and do the same for the negative terminals of all the panels. Then cover the joints of positive and negative wires individually with insulating tape.
Step 3: Attach the Charge Controller
Connect the positive wire of the panel to the positive terminal of the charge controller and the negative wire to the negative terminal of the charge controller. Our solar charge controller has a USB Type-A port on it. The charge controller has an internal voltage regulator which converts 12V DC to 5V DC, enabling it to charge USB-powered devices. In USB modules, generally pins 1 and 4 are used as 5V DC and ground respectively. Using this USB port, you may charge electronic devices with USB interfaces such as mobile phones, tablets, and smartwatches.
The solar charge controller prevents overcharging/overvoltage which could otherwise cause the battery to heat up. Overheating can cause damage to the lifespan and performance of the device’s battery.
Step 4: Install the Battery
Installing a battery ensures auseful power backupin situations where solar charging is unavailable due to bad weather conditions or at night. We are using 12V DC batteries for storing electric current. We arranged these batteries in a parallel configuration which results in the provision of the same voltage, i.e. 12V, through this parallel combination. However, a parallel combination increases the current capacity.
You should choose the battery capacity (one unit or multiple) based on the load requirement and the solar panel’s charging capacity. Connect the battery interface of the solar charge controller to the battery terminals using thick metallic wires.
Step 5: Finalize the Wiring
Make sure to connect all the components correctly and tightly to avoid sparking. Also, cover the joints to avoid short-circuiting. Use good-quality thicker wire for interconnection as it reduces conductor losses. It is generally recommended to place solar panels, charge controllers, and batteries close to each other to avoid lengthy electrical wiring—the latter can result in greater electrical loss and lower the efficiency of the solar system.
Step 6: Test the Charger
To test this system during daytime for battery charging, press the on button on the solar charge controller. Observe the voltages that appear on the charge controller. Also monitor the current flowingusing a digital multimeteror digital clamp meter.
You will observe that the charge controller displays the voltage on the battery and solar panel. The charge controller also shows the load current for this system, when a DC load is connected to it.
When the 12V battery achieves a voltage of around 14V DC on the solar charge controller, it disconnects the charging from the solar panel, to protect the battery from overcharge. You can observe this by monitoring the solar panel voltage, which might exceed 16V DC on sunny days.
Next, connect a USB device or smartphone directly to the solar charge controller using a USB Type A connector. The USB port provides 5V DC, which is internally regulated/down-converted from the battery. As you do this, you’ll notice the connected device begins to charge. Moreover, you’re able to also observe the current drawn by this load.
In addition, this system can power devices other than through a USB interface; i.e. you can use the 12V interface for DC bulbs, DC fans, etc. All you need to do is to connect these to the load interface on the charge controller. The load symbol (e.g. a bulb) represents this interface on the charge controller.
You can further enhance this DIY project to make a small and lightweight portable platform to use for charging smartphones and USB-powered devices without using a battery. However, it will work during the day only.
The Benefits of a Solar Charger
This solar-powered arrangement can help you improve the portability of your device and reduce the reliance on conventional electrical power distribution systems. Solar charging also improves efficiency by avoiding losses incurred during the AC-to-DC conversion in conventional systems. In solar-powered systems, you can avoid these losses as all storage/charging is conducted in DC; however, it may require up-conversion or voltage regulation.
By utilizing solar energy in your home, you can substantially cut down your electricity expenses. There are plenty of other solar-powered projects you can build yourself such as a solar-powered streetlight, solar-powered pool heaters, solar-powered Bluetooth speakers, etc.
