How I Convert Lead Acid Battery Into 12V 15Ah Lithium-ion Battery Pack

So Hey Guys in today's article. I am going to teach you How I Converted a Lead Acid Battery into a Lithium-ion battery.

What is the advantage of a Lithium-ion battery?

  • Fast charge in less time.
  • 3-4 times longer backup then a lead acid battery
  • No worries for 5 years.

If you read this article from beginning to end.

So it's my guarantee that you can easily make any type of battery pack, like 12 Volt, 24 Volt, 48 Volt so one… 

And Yeah one more thing I also mentioned how you can make this lithium-ion battery pack at a very Low price.

What's your need?

Before making the battery pack you have to decide what's your need? You have to decide what the voltage or Ah will be for your battery pack. 

For Example: If you want to make a 12 volt 7ah battery pack, 24 volt 24 ah, or 48 volt.

First know what the output voltage and mAh will be for your battery then select a lithium ion cell according to your battery pack.

So I hope you know what's your need? I want to make a 12 volt 15 Ah battery pack.

Lithium-ion battery comes in several ampere range


  • "3.7V 1200 mAh"
  • "3.7V 2000 mAh"
  • "3.7V 2200 mAh"
  • "3.7V 2600 mAh" or "3.7V 3000 mAh"

To measure the power of any battery two things are Important. Volt & Amp

As you can see on Ex:1 This battery is 3.7V 1200 mAh And look at the Ex:2 This battery is 3.7V 2200 mAh. 2200 mAh means 2.2 Amp And the one which is 1200 mAh the battery is 1.2 Amp. 



And similarly the lead acid battery is of 12 volt 7 amp.

When the positive terminal of all the batteries will be connected. and the negative terminal of all the batteries will be connected together, then we call it parallel connection. As you can see on this image. I have connected 2 batteries in parallel.

And in series the negative terminal of the battery has been connected to the positive terminal of the second battery. Then we call it a series connection. As you can see on this image. I have connected the battery in series.

So now you know how Series connection & Parallel Connection looks like.

But what is the difference between Series & Parallel?

When you connect the battery in parallel, mAh will increase but the voltage will be the same 3.7V and when you connect in series the voltage will increase. You can see on this video I am checking the voltage using a multimeter.

So as you see on the video when I am checking the voltage of the series battery the voltage has been increased. When I was checking the voltage of parallel the voltage is 3.7v but the backup has been increased

  • Parallel Ex: 3.7V 2200 mAh + 3.7V 2200 mAh = 3.7V 4400 mAh

  • Series Ex: 3.7V 2200 mAh + 3.7V 2200 mAh = 7.4V 2200 mAh

So I hope you know the difference between Series & Parallel Connection. In short, series connection increases the voltage and parallel connection increases the backup.

So this is the basic concept that you have to know. Now let's make it a 12 volt battery pack.

So this is the connection you have to connect in this manner to make a 12V 8.8 Ah Battery.

What is the use of BMS in battery pack:

So now our battery pack is ready but we have to connect the BMS (battery management system) . What is the work of the BMS in battery? Basically BMS will protect from overcharging deep charging and also provide protection and balance charging. So if you are thinking of making a Lithium-ion battery pack then I will say to use BMS.

BMS is very important to charge the battery in a balanced way. If you don't know, let me tell you BMS comes in the different Volt/Amp range. You have to select BMS according to your battery. In my case I am using a 3S 12V 30Amp.

Wiring Explain of BMS:

3S 12 Volt 30 Amp BMS Circuit Diagram:

I hope you know how to connect BMS with a battery pack. So now your 12 volt battery is ready to use!

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