# How to Built Li-ion Battery Pack !

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In this project, I will show you how I made Li-Ion battery pack using 18650 cells which can be useful to power e-bike motor or a quad-copter. I'm working on a secret project so do forget to follow me for more.

So let’s get started.

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## Step 1: Watch the Video!

If you get bored of reading all the stuff then you can watch my video on Youtube

## Step 2: Planning !

To start with first, we have to decide the output voltage. In my case, I require 24V. As we all know 18560 cells provide a nominal voltage of 3.7V so after a bit of calculation we will need 6 cells in series to get the output.

If you want higher capacity, you can add 6 more cells in parallel to double the capacity.

## Step 3: Need Some 18650's!

For this battery pack, I’m using cells from Samsung you can even use Panasonic cells as well!

here are links to some good quality cells and charger,

Panasonic

Samsung(Pink)

Samsung(Green)

iMAX B6AC V2 6A Balance Charger

These are affiliate links it helps and supports me :)

## Step 4: Battery Check-up

Before we proceed ahead we need to make sure all the cells have the same voltage. If not charge them using TP4056 or with a balance charger.

This is mandatory because if cells have different voltage cells may end up charging each other with an unhealthy amount of current. which can even lead to the explosion of cells.

## Step 5: Pre-Tinning Cells

I don't have a spot welder so I'm using good old soldering method. However, soldering is not recommended because it heats up the cells but if you are quick enough you can do it without damaging the cells.

To start building the battery pack first I used sandpaper to make the surface rough so solder can stick to it properly after this I pre-tinned the cells. Then I used a bit of a hot glue and stuck all the cells in an alternating pattern for easy soldering.

## Step 6: Soldering !

For the soldering process, I'm using 2.5 Sqmm wire of which I made about 1 inch long pieces which will be used later-on to connect the cells in series and also do not forget to pre-tin them as well.

Then I started the soldering process, connect the anode of the 1st cell to the cathode of the 2nd cell until you are done and you will end up with two unsoldered terminals which will be your output terminals.

Now I soldered the XT60 connector which I made earlier which can easily handle high current.

## Step 7: Balance Connector!

The universe needs balance then why not battery pack? (Thanos did nothing wrong :P)

Okay jokes apart, Since this is a multiple cell battery pack balance charging is mandatory so I used a 6 cell balance connector to connect each individual cell as shown in the phots

The leftmost pin is the GND and every next pin will be a multiple of 3.7 v i.e. it will connect to next cell.

And that's it our battery back is complete!

## Step 8: Thank You !

I hope you enjoyed, If you like my work

Feel free to check out my YouTube channel for more awesome stuff: https://www.youtube.com/c/Nematics_lab

You can also follow me on Facebook, Twitter etc for upcoming projects

https://www.facebook.com/NematicsLab/

https://www.instagram.com/nematic_yt/

https://twitter.com/Nematic_YT

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## 7 Discussions

your project is not for everyone, danger if some step do wrong and don't know what you are doing, expose and the design can be better and safer

1 reply

I doubt anyone who is this fearful of Li ion cells will be working with them. If you are this concerned with the risks, google "Vruzend kit"

using hot glue and heating the cells soldering wires doesn't seems a good idea. Furthermore, you need a BMS.

1 reply

you would be hard pressed to find an OEM battery pack from any manufacturer that doesnt use hot glue. Soldering has been tried and proven to work. he included wiring to have a BMS, what more do you want? should we just ban 18650s altogther because they are dangerous?

How would I connect a balance charger to the circuit if I decided to add another 6 batterys to double the capacity? My battery charger now can only have 7 pins on the balance charger.

1 reply

BMS is mandatory if you use more than one cell in parallel and if you know what you are doing then it's fine.