DIY Power Bank Circuit

Published  January 2, 2018   39
DIY Portable Power Bank Circuit to Charge Your Cell Phone

The features of the digital products are growing enormously which triggers the frequent usage of smart phones in several applications.  Thus the battery backup time is getting decreased. It will be fun to build a Power Bank for Mobile Phone as spare charging source for emergency purpose which is also portable. In this article we will discover how to make a power bank with a super simple power bank circuit diagram.

The important factor to be considered while working with lithium batteries is protection circuits and quality of batteries. But, when this comes to 18650 cells the risk factor is less compared with pouch batteries. Good protection is offered by few readymade modules available in market.

Components required for Power Bank Circuit:

  1. 18650 Lithium cell
  2. TP4056 Module with battery protection circuit
  3. 3V to 5V boost converter with 1A current control
  4. Slide switch

components for mobile phone power bank circuit

Power Bank Circuit Diagram:

Below is the circuit diagram for our power bank. As we can see its fairly easy to make a power bank with li-ion battery, TP4056 module and a boost converter.

mobile phone power bank circuit diagram


18650 Lithium Cell:

18650 lithium cell is the important part of this power bank circuit. The term 18650 cell is due to the cell dimension, it is cylindrical in shape with 18mm diameter and height of 65mm. Also these cells are available in different capacities corresponding to applications. They are rechargeable cells with 3.7v output.

The method of charging a single lithium ion cell requires two stage,

  1. Constant current (CC)
  2. Constant voltage (CV)

During CC the charger should supply constant current with increasing voltage till the voltage limit. Next a voltage equal to maximum limit of cell should be applied during which the current declines steadily to the lower threshold current (i.e., 3% of constant current). All these operation is carried out by the TP4056 module which is highly reliable and affordable choice.


TP4056A Module:

This is a low cost charging solution to charge any type of single lithium ion battery. Mobile batteries, 18650 NMC cells, Lithium pouch batteries, etc. The micro B Receptacle and easy adjustable 1A output current control makes it reliable choice to charge any low capacity batteries. It can be connected to any wall socket based mobile charger or any sort of USB to micro B cable. It is made of an integrated PMOS load switch architecture, hence reducing overall additional components.

TP4056A Module

The module also has two indications, Red color LED (L1) to indicate the ongoing charging condition. Blue color LED (L2) indicates the completion of charging. This module can operate at high ambient temperature since the thermal feedback can regulate the charge current. The charge voltage is 4.2V and current can be adjusted by changing a resistor in the module. But, the default current will be 1A when bought.


The protection circuit includes,

1. DW01x – Single cell lithium ion battery protection IC with dual MOSFET control feature. Below is a application test circuit provided in the datasheet.

TP4056A Application Diagram


2. FS8205A – Dual N-Channel enhancement MOSFET with common drain connection. Also the drain to source resistance is low. The gate of the MOSFET is controlled through the DW01A IC.

Thus, the DW01A provides Overcharge control, Over discharge control, Overcurrent control by controlling the MOSFET through the circuit.


Micro USB 3V to 5V Boost Converter:

Lithium battery is only providing 3.7 volt here but we need 5v to charge the Cellphone, so we have used 3v to 5v boost converter module here. This boost converter module has high efficiency of upto 92% and integrated over current protection. The topology used inside is Non-isolated step-up converter which operates at a switch frequency of 1MHz. The overall power output that can be drawn out of this module is 5W. The output voltage can be adjusted to 12V by changing a resistor in module but the maximum current will be 400mA. But by default this module is available at a rating of 5V, 1A. Under this rating the output ripple is 20mV pk-pk. The module also has USB type-A female receptacle which is universal. Any USB power cable can be used as interface. The operating temperature of the module is -40°C to +85°C. It also has an LED indication to indicate the presence of supply from battery source. The Red color Led indicates the presence of power supply across the terminals.

5V Boost converter module

We previously used the same module in Solar Mobile Phone Charger Circuit.


The modules were connected and fixed to a plastic plate using hot glue.

mobile phone power bank circuit with lithium cellcell phone power bank circuit


Charging the Power Bank Circuit:

Red color LED indicates the battery charging in this power bank circuit,

red led charging signal for charging mobile phone power bank


Blue color LED indicates the charge complete,

blue led charging complete signal for mobile phone power bank


Charging the Mobile Phone with this Power Bank:

1. Connect the USB to micro B cable to the output of boost converter.

charging mobile phone using power bank circuit


2. Turn the slide switch ON.

charging mobile phone using power bank circuit


3. The mobile phones battery starts to get charge from the power bank

Power Bank Mobile Phone Charger Circuit


So this is how you can easily make Power Bank Circuit for charging your Smart Phones. Below you can find the video which demonstrates how to build 18650 Lithium Cell based power bank circuit.


Have any question realated to this Article?

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Submitted by M C on Fri, 09/22/2017 - 08:52


How can you increase the powerbank's capacity, like for example bout 10000mAh?
Would there be any changes with regards to the module used?

Submitted by Arvind Ragupathy on Mon, 10/02/2017 - 17:49


To increase capacity number of lithium cells can be increased in parallel.
When using the same module arrangement the charging time increases
equally to the capacity, Eg: 10000mAh takes about 10 hours to charge from
empty to full. But, there is no other problem in using in that way. Ensure the
cells that are connected in parallel are of same capacity (For eg : 3.6V, 2200mAh).

So there is no need to be worried about balance charging? and where would we be able to connect a higher input voltage if the batteries allowed for it, or would we just create a whole new circuit leading to the positive and negative ends of the batteries in parallel in order to charge at a higher voltage?

This module is designed to charge a 18650 cell whose full charge voltage is 4.2V. Also the charging current of these cells are rated less than 1A. So why do you need a 2A charger? A charging current of 2A or more could easily kill a 18650 cell.. 

The idea of using two modules in parallel might actually work though 

Submitted by lumy on Tue, 01/02/2018 - 17:38


this circuit does not have an over-discharge protection? because the booster is fixed to the battery, hence the TP4056A can't prevent over-discharge?

There is no over-discharge protection. The booster is connected in parallel to the battery and TP4056, thus even if the TP module was powered on it would have no control over the discharge from the booster. To fix this you need a discharge protection IC in series with the booster and battery.

Submitted by Sohail on Thu, 04/05/2018 - 19:11


My power bank is crashed when i connect the bettery terminal on the circuit board the blue light begins to gow with a sound "geeeeeeeeeeeeeeee............"

Submitted by Arakel on Mon, 05/14/2018 - 23:56


The circuit you give is different from the PCB. On the circuit you have the switch between the 2 pluses, on the PCB you have it between the 2 minuses. You do not give good explanations how to connect the switch and you do not show the connections well on the PCB pictures.

The switch is used only to break or make the connection. It can either be present on the positive rail or on the negative rail. However having it on the negative rails is a bit more advantages 

Submitted by mike on Sun, 05/20/2018 - 23:29


i don`t see a deep discharge protection. if it is the step-up booster i think it is.
It discharge your battery to almost a 0,5 volts lithium battery`s dont like that and wil posibley be dead or get dangerous after it, becouse the chemestry inside the battery wil get unstable. inside your phone te battery is monitored by a bms battery monitoring system en wil never !!!! be fulli dicharged.
so my 2 cents, get a undervoltage protection at a rc hobby shop for example.

Submitted by Microsoft Edge… on Thu, 06/14/2018 - 23:16


Enormously the modern technology advances up to a high range, using a smartphone we can get several features.

Submitted by Prashant K Misra on Sun, 06/24/2018 - 14:03


What changes are required in boost board to give 4.5v

Submitted by maltesh on Wed, 07/11/2018 - 23:00


what are disadvantages increasing the number of cells for 2000 mah powerbank circuit ?

Submitted by Din on Thu, 07/12/2018 - 10:44


Thank you for the instructions. I made it. but the boost converter is heated when the mobile phone is charging.Is there any solution to reduce the heat. Or , does the guage of wires matter for this situation as the wires can't bear the current?

How many hours it will take to charge a single 18650 battery 2000mah

Excellent tutorial. Much appreciated! Hopefully you are still checking this. I was actually in the process of making one of these when I cam across this. I had two manin questions,

#1. is the switch necessary? Is the purpose to keep from the phone battery reversing and draining into the power bank? If not, and if it cen be made without the switch is there something in the circut that is preventing the reverse draining? 

#2. If I already have a protection circut on a lipo battery, is the 4056A necessary? or could I use a simple 5 pin micro usb board with no circuitry?


Brian Martin 

the  batteries  are  well charged  and  when  the  load  charging  switch is  switched  on ,  after  few  seconds  the  out  put  at  the USB falls to zero.

This  happens  on ' no load  '    and   also  'on  load  '  condition.

please  suggest  a  solution.