Geek DIY: Teach you to make a simple "solar" power bank

In this sharing, I will show you step by step how to make a simple solar power bank by hand. At the same time, because of my personal preference, the production process of the beautiful and artistic wooden exterior will also be included.

You may have seen similar sharing elsewhere, but I hope that in addition to complaining, you can see the true inner nature of the geek I admire - do it and be willing to share, and I also look forward to seeing your masterpieces!

5V USB boost DC circuit, 6V solar battery, three No. 5 Ni-MH (nickel-metal hydride) rechargeable batteries, battery holder for three No. 5 batteries, 1N914 diode, toggle switch, coil, heat shrink tube, some wires.

In addition, to make the wooden case shell part, you will need: 18-inch plywood, 16 x6-32 screw nuts.

The tools used include:

First of all, you must be clear that the standard for charging most electronic products is 5V/500mA, and there are two ways to achieve this condition:

One is to use a large solar cell over 5V and then reduce the voltage to 5V. But this method will make our power bank seem very heavy and costly.

The other is to boost the voltage to 5V through small solar cells and some ordinary rechargeable batteries. This is a common practice for small commercial power banks, and it is also the method I use, which is cost-saving and small and lightweight.

The key to the whole operation is the boost circuit, which is what we usually call a transformer. Using the coil, we raise the voltage to 5V and ensure the stability of the voltage. This is how our USB output is complete.

Since my boost circuit can carry a minimum voltage of 2V, this must be taken into account when choosing a power supply. After some of my testing, I finally chose to use three 1.2V rechargeable batteries and 6V solar cells to keep the power supply stable (can be adjusted according to personal needs)。

The above is a specific circuit diagram, the diode is used to prevent the current from the battery from flowing into the solar cell, and the toggle switch can be used to switch the circuit. The circuit can be expanded or reduced according to the actual situation.

During the design process, I chose to use a laser cutter to cut the planks to create a wooden box-type shell out of personal preference. The various parts of this box are perfect for this project, and of course you can choose to make a case that you love using plastic, rubber, etc. I personally do not recommend using a metal case as it can be bulky and difficult to modify.

The illustration of the entire wooden shell is below, so I believe it will not be difficult for you.

Weld two of them to the positive and negative poles of the solar cell, and if you are using a laser to cut, remember to attach sponge tape to the bottom of the solar cell and peel off the protective film of the tape.

Connect the negative pole of the toggle switch to the solar cell, then connect the remaining 6-inch wire to any of the remaining pins of the toggle switch. It is important to note that the pins of the toggle switch are made of metal and plastic, so do not solder too long to avoid melting.

Connect the remaining feet of the diode to the small hole in the positive electrode of the USB port, solder it, and cut off the excess. In addition, use a wire to connect the negative electrode as described above.

Mark the positive and negative electrodes under one wooden board, pass the positive wire of the diode through the hole of the positive label, pass the wire of the negative electrode of the toggle switch through the hole of the negative label, weld them separately, and finally remove the excess wire.

This way the switch will be under the board. In addition, the white LED light is meaningless and can be cut out.

Next comes the assembly of the wooden shell. Although the material is wooden, you should try to be as careful as possible during the assembly process and not use too much force.

To ensure that the screws and nuts are intact, the assembly starts from the bottom, and the whole process needs to be as compact as possible. I believe that with the following process diagram, you can also complete it well.

Well, it's done, after completing the above processes, a practical and artistic solar power bank is complete! Due to the battery used, it can only charge small and medium-sized electronic devices such as mobile phones, Mp3s, and Pads, so I hope you won't be disappointed.