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Power Bank using old batteries

Powering devices had a major role in our life, modern social standards increase the usage of electronic gadgets around us and if we mentioned electronic gadgets, power devices have an inevitable part to do.

Along with smartphones, mostly every one of us carrier power banks for our recharging purposes, because the capacity of the phone didn’t have any role in its consumption rate.
So on last week for curiosity, I just open my power bank case, I realize it is a small circuit board with only 3 battery cells connecting each other.
I really get confused because, this tiny circuit arrangement without any high-level components should have a maximum price of 100 to 200rs, but we spend 2000 or 5000rs for it.
so I had an idea to build a power bank using old mobile batteries, arranging old electronic gadgets batteries like laptop batteries are at everyone’s home, so I decided to make a power bank using two types of batteries.
1.using mobile batteries
2.laptop batteries (Li-ion)

Battery power bank explanation

Both these batteries are available in everyone’s home, we have to use both these rechargeable batteries to build a power bank;

1.Old mobile batteries

Old mobile batteries are easily removable from mobile phones and its terminal marked in its body properly, those years replacing such batteries don’t need any special tools and service persons.
But we have so many doubts at its usage in power banks, because of its capacity but the reality is that such batteries have a capacity of 80% is left after 2years of its usage.
And also we have to check whether it’s overheating and swelling problems in the old batteries.

How to make Power Bank using mobile phone batteries


Components used

1.3 or more rechargeable phone batteries.

2.Charger module

3.Connecting wires


Working process

First, you have to test the batteries and make sure that charging and discharging are proper, and after that, you don’t notice any unusual overheating or swelling at the batteries it is perfect for making power banks.
First of all we have to clear the surface of the mobile phone batteries and then remove the plastic layer in its body, because the compatibility is the main factor as to when we handling a power bank.
Clear off all plastic coats at battery terminal portions which indicating positive and negative ports, then place all batteries uniformly and terminals such as positive and negative are been arranged in a straight line and stick all batteries in such a way and then stick it together using a glue gun.(Here we can use insulation tapes for sticking each other).
Next we have to connect positive and negative portals separately, interaction connections between battery ports are made using soldering iron and we have two wires connected outside for polarity differences, these connections are made for compatibility at the battery arrangement.
Next we have to apply glue gun in soldering portions of the batteries for insulation protection.
After that we have to place batteries in a plastic box before that we have to stick our charger module at its surface and this will make it more compact.
Then make our connections between terminals of battery and charger module, after that apply glue gun at its conducting portions for safety precaution.
The output voltage of this circuit is measured around 5.3 volts and charging properly, power adjustments and LED indication for the functions are provided in the module itself.

Laptop battery power bank

Components used

1.Three or more lithium-ion batteries

2.Charging and protection module

3.5-volt dc step up converter module

4.Connecting wires

Laptops usually have lithium-ion batteries, it looks like normal AAA batteries.
Laptop batteries and power banks are built with these batteries, and after losing its capacity we throw it away in our scrap but the truth is, if it is a laptop battery or Power Bank battery, it is an arrangement of 6 or 8 lithium-ion batteries connecting in series, so damages happened at one cell will cause damage, but normally our services persons replace it with a new one but they make an offer with this old batteries for a business trick that is for reusing possibility of its cells, we didn’t mind it because of the busy schedule.

Making process

First of all, take three lithium-ion batteries and stick it together, each lithium-ion batteries are named as cells, and this arrangement is called the batteries
Check out the damages in each battery, we mentioned earlier about the mobile batteries, you can apply it here that overheating and swelling.
And connect our two modules with its positive and negative terminals and made insulation enclosure with a proper plastic box and make holes for connections.

Modulus used

3400mAh rechargeable batteries are used for this Power Bank project, lithium-ion batteries are dangerous at its operation, so proper protection is needed for its usage.
Here we are using lithium-ion batteries protection and charging boards because lithium-ion batteries had a particular charging pattern.
Over discharging and overcurrent protections are needed for its usage, 4.2v limit is set in the board for the safety charging operation.

The 5-volt dc step-up converter

operation wise, it is a transformer and a power supply circuit, working of this circuit is like, it will convert our old battery signal into a square wave DC supply for changing mobile phone, this operation has happened with the usage of a coil at the board itself.


Today we are facing e-waste pollution all over the world because electronic gadgets e-waste deposition in nature will damage our soil and natural ecosystem.
Here is the importance of reusing technology, batteries, and chemical used on it cause damages.
In this project we initialize a new habit of reusing technique using old rechargeable batteries with minimum effort and minimum cost, this will cost around 100 rupees.


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