Just an Introduction
Hi everyone, here is my first instructable. Recently, I made myself a Power Bank.
I found that it is slow to charge my phone with standard 5V 1A power supply bought from the market.
Moreover, it is hard to find a good power bank when you live near China. So, I decide to make one for myself!
Here is what it looks like after I finished it within a day.
Step 1: Prepare What You Need
Materials are simple, you can get whatever you want to make a power bank. Just a few old Lithium ion Battery from toys or old cell phones, broken power bank or so on. If you are using more than one Lithium ion Battery, make sure they are in the same capacity (eg, 2 x 2200mAh 18650)
What I use here is 4 x 454261, each with 1100mAh, the yellow thing on the top of the battery is the protection circuit. Make sure your battery have something similar to that.
For the other components, I used a TP4056 Lithium Charging Control board, a USB port, a switch, q 3D printed casing and a DC DC converter which you can easily pick one up online. Also there is an integrated converter which already connected to a USB port, that is a step up transformer for 5V 600mA. In case you can't find something similar to that, DIY ! You can find many tutorial on making a 3.7v to 5v DC to DC converter.
The base and the panel which the USB port and switch was fixed on were included here.
Step 2: Wire Them Up!
Wiring is as simple as the following
1. Connect the positive terminal and negative terminal to the charging board
2. Plug in the charger, check if the red LED on the charging board lights up.
3.If the battery is all right, Connect the positive terminal of the battery to the switch
4. Wire the switch to the transformers, Then to the USB ports.
5. Connect the ground of the battery to the two grounds on the transformer
Step 3: Circuit Check
If your connection is correct, the wiring should look something like this
Check the wiring and voltage across different points using a multimeter.
The two usb ports should give a reading between 4.8 to 5.2 V.
Step 4: Test Fire~
After building the circuit, charge your Power bank with 5V 800mA .It is recommended that don't charge your Power Bank with more than 1A.
Wait until the battery is fully charged and the green light on the charging board should light up after that battery reached 4.2V.
Meanwhile, give a tiny adjust over the variable resister on the DC DC converter to a value that you like. For example, I adjusted it to 5.85V so that it has enough voltage and current to charge my tablet.
DON'T GO OVER 6V OR OTHERWISE YOUR PHONE MAY BE DAMAGED.
Step 5: Casing and Packaging
Casing is important. So I laser cut a 3mm thick Acrylic sheet with 13.5 * 6.5cm and place it on top of the base. This sheet can protect the user from injuring if the Lithium ion battery is exploded due to over charging or short circuit.
You can also seal it with silicone glue if you want to give it a better water proof casing.
Step 6: Finished!
Lastly, stick the warning label and capacity of my Power Bank, my new Power Bank has been finished!
Step 7: Technical Questions and Info
1. Why there are 2 kinds of transformer in this power bank?
Ans: The smaller one is for normal charging. The larger one is for supplying higher current and voltage. In this case, smaller one is 5V 600mA and the larger one can supply 5V up to 3.2A!
2. What 3D printing material should I use?
Ans: The power bank doesn't generate much heat, PLA or ABS will be alright.
3. If my battery didn't have the yellow things connected, can I use them for my project?
Ans: I don't recommend to use that as Lithium ion battery without protective circuits maybe dangerous. Just buy a protective circuit for your battery or buy a charging board which integrated the protective circuit will be a better choice.
4. What is that logo on the first picture?
Ans: That is the logo I use on all my projects. There is no special meaning on it.
5. For further help, feel free to leave your comments below. I will reply you as soon as possible.