NewStats: 3,264,063 , 8,182,472 topics. Date: Monday, 09 June 2025 at 01:55 PM 6i2q

billyG:

Does this means all d side up is welded +ve & d underside is welded -ve in parallel connection?

Yeah that’s correct. One side is positive and the opposite side is negative. I was like you too 😁

Those 24cells are all connected in parallels already, meaning that the positive terminals of each cells are welded and connected all together, and the negative terminals are connected all together as well. That is called 24P. Then each of them will be connected in series to form 3 series. This is why it is called 24P3S. And for this to work, you will need a 3S BMS (I.e a BMS for 3 Series connection)

To help further (I don’t know if it’s necessary though. But I love maths😁)Now let’s do a quick maths:
Assuming each cell has a rating of 3.7V and 3.2Ah

The 24 pieces that are all in parallel will give:
= 3.2Ah × 24 = 76.8Ah capacity and 3.7V.

Nb: When you connect in parallel, you increase the capacity (I.e the Amps) but the voltage doesn’t change. This means that the 24 cells in parallel has a constant voltage of 3.7V but Ampere of 76.8Ah in total.

Let’s continue. So now that you have 3 units of 24Parallel cells, it means we have 76.8Ah 3.7V in 3 places. He will go on to connect the 3 of them in series. Let’s do the maths.

that connecting in series increases the voltage but keeps the Ampere constant, so let’s add up the 3 voltages:
3.7V + 3.7V + 3.7V = 11.1V
Total capacity will then be:
11.1V & 76.8Ah
=11.1 × 76.8
= 852.48Wh

But ofcourse, the capacity might not be up to that at the end of the day.

I hope this helps.

BigDickProblems:


Yeah that’s correct. One side is positive and the opposite side is negative. I was like you too 😁

Those 24cells are all connected in parallels already, meaning that the positive terminals of each cells are welded and connected all together, and the negative terminals are connected all together as well. That is called 24P. Then each of them will be connected in series to form 3 series. This is why it is called 24P3S. And for this to work, you will need a 3S BMS (I.e a BMS for 3 Series connection)

To help further (I don’t know if it’s necessary though. But I love maths😁)Now let’s do a quick maths:
Assuming each cell has a rating of 3.7V and 3.2Ah

The 24 pieces that are all in parallel will give:
= 3.2Ah × 24 = 76.8Ah capacity and 3.7V.

Nb: When you connect in parallel, you increase the capacity (I.e the Amps) but the voltage doesn’t change. This means that the 24 cells in parallel has a constant voltage of 3.7V but Ampere of 76.8Ah in total.

Let’s continue. So now that you have 3 units of 24Parallel cells, it means we have 76.8Ah 3.7V in 3 places. He will go on to connect the 3 of them in series. Let’s do the maths.

that connecting in series increases the voltage but keeps the Ampere constant, so let’s add up the 3 voltages:
3.7V + 3.7V + 3.7V = 11.1V
Total capacity will then be:
11.1V & 76.8Ah
=11.1 × 76.8
= 852.48Wh

But ofcourse, the capacity might not be up to that at the end of the day.

I hope this helps.

God bless you for this detailed explanation

officialfestus:
7s 2.4kw in progress.

you mean this pack is 2.5kw?

Good afternoon engineers, pls, I have 2500mAh and 2000mAh lithium ion battery cells that I am gathering to build a 7s pack to attain 24v battery system. Can I mix those capacities together in one 7series pack or Isbit possible for me to build two individual 4s 12v pack of the different mAh capacities to later connect both pack in series to get 24v battery system. And how can I balance that?

Thank u all.

@officialfestus, Queed & co

It is clear that people on here are interested in your builds and that you do make builds for others on request.

So can I suggest that instead of endless msgs here where people are asking you price and s, that you just make at least ONE of yours available.

It does not have to be your phone number, it could be your telegram (that does not have to have your number attached), instagram or any other , but please put it in your profile/signature so people can see it without having to drop msgs here.

We do understand this is a DIY thread, but people will have questions that they want to ask one on one and providing something on your signature will help.

@dollarnaira

Not directly related. But someone wants to discuss with you about something regarding Re and he asked me for your number, which is also not available on your signature. I am sure he has probably emailed you, pls check.

AndroBlaze:

@officialfestus, Queed & co

It is clear that people on here are interested in your builds and that you do make builds for others on request.

So can I suggest that instead of endless msgs here where people are asking you price and s, that you just make at least ONE of yours available.

It does not have to be your phone number, it could be your telegram (that does not have to have your number attached), instagram or any other , but please put it in your profile/signature so people can see it without having to drop msgs here.

We do understand this is a DIY thread, but people will have questions that they want to ask one on one and providing something on your signature will help.

@dollarnaira

Not directly related. But someone wants to discuss with you about something regarding Re and he asked me for your number, which is also not available on your signature. I am sure he has probably emailed you, pls check.

My number is like pure water here.
See it below.

dollarnaira:


My number is like pure water here.
See it below.

Seen and sent 👍

Binsule:
Good afternoon engineers, pls, I have 2500mAh and 2000mAh lithium ion battery cells that I am gathering to build a 7s pack to attain 24v battery system. Can I mix those capacities together in one 7series pack or Isbit possible for me to build two individual 4s 12v pack of the different mAh capacities to later connect both pack in series to get 24v battery system. And how can I balance that?

Thank u all.

You have no easy way to balance the second option but you can try the first option but be careful and be warned it is not safe it can cause fire when you treat those cells anyhow

@dollarnaira, officialfestus, Queed etc.

Please I have a very interesting question. So I use a locally constructed system with a 40Ah 12.8 capacity. Each cells are rated 3.2V and 20Ah. They were connected 2p4S connection to give the 40Ah & 12.8V capacity. It’s all working well.

But my question is based on the lessons learnt here so far. Can I go and get those quality cells of the same capacity myself at Alaba or even Arena and just connect an extra cell to each of the 2P connections?

If I do so, I’ll have 3P4s connection instead of the original 2P4s connection. This will achieve 60Ah 12.8V. Why this it’s important is because to another capacity, I’ll spend around 100k of the same capacity. Please let me know if this is feasible considering the fact that there is an existing BMS, Bulk converter etc., in the system.


Can I just connect the 4 cells each on the existing 2p connection’s to make it 3S connection without any issue on the system?

That’s just the summary of my question. Thanks.

Modified: 20AH not 5AH

Marykhay:
@dollarnaira, officialfestus, Queed etc.

Please I have a very interesting question. So I use a locally constructed system with a 40Ah 12.8 capacity. Each cells are rated 3.2V and 20Ah. They were connected 2p4S connection to give the 40Ah & 12.8V capacity. It’s all working well.

But my question is based on the lessons learnt here so far. Can I go and get those quality cells of the same capacity myself at Alaba or even Arena and just connect an extra cell to each of the 2P connections?

If I do so, I’ll have 3P4s connection instead of the original 2P4s connection. This will achieve 60Ah 12.8V. Why this it’s important is because to another capacity, I’ll spend around 100k of the same capacity. Please let me know if this is feasible considering the fact that there is an existing BMS, Bulk converter etc., in the system.


Can I just connect the 4 cells each on the existing 2p connection’s to make it 3S connection without any issue on the system?

That’s just the summary of my question. Thanks.

Modified:
cell rating is 20AH not 5AH. Thanks in anticipation.

Marykhay:

Modified:
cell rating is 20AH not 5AH. Thanks in anticipation.

Are the cells cylindricals or prismatic?

dollarnaira:


Are the cells cylindricals or prismatic?

They are Cylindrical.

dollarnaira:


Are the cells cylindricals or prismatic?

Something like this

Marykhay:

Something like this

Valto sells the 23ah brand new.

dollarnaira:


Valto sells the 23ah brand new.

I know he does, but can I just weld three pieces of the same capacity of cells in each of the 2P connection? To make it a 3P connection. Pls I hope you understand my question.

Marykhay:


I know he does, but can I just weld three pieces of the same capacity of cells in each of the 2P connection? To make it a 3P connection. Pls I hope you understand my question.

Yes
You can do 1000 sef

BigDickProblems:


Yeah that’s correct. One side is positive and the opposite side is negative. I was like you too 😁

Those 24cells are all connected in parallels already, meaning that the positive terminals of each cells are welded and connected all together, and the negative terminals are connected all together as well. That is called 24P. Then each of them will be connected in series to form 3 series. This is why it is called 24P3S. And for this to work, you will need a 3S BMS (I.e a BMS for 3 Series connection)

To help further (I don’t know if it’s necessary though. But I love maths😁)Now let’s do a quick maths:
Assuming each cell has a rating of 3.7V and 3.2Ah

The 24 pieces that are all in parallel will give:
= 3.2Ah × 24 = 76.8Ah capacity and 3.7V.

Nb: When you connect in parallel, you increase the capacity (I.e the Amps) but the voltage doesn’t change. This means that the 24 cells in parallel has a constant voltage of 3.7V but Ampere of 76.8Ah in total.

Let’s continue. So now that you have 3 units of 24Parallel cells, it means we have 76.8Ah 3.7V in 3 places. He will go on to connect the 3 of them in series. Let’s do the maths.

that connecting in series increases the voltage but keeps the Ampere constant, so let’s add up the 3 voltages:
3.7V + 3.7V + 3.7V = 11.1V
Total capacity will then be:
11.1V & 76.8Ah
=11.1 × 76.8
= 852.48Wh

But ofcourse, the capacity might not be up to that at the end of the day.

I hope this helps.

Nice explanations,now if I have 8 ( 3.2v) Lifepo4 cells,I want to build 25.6v what will d combination called and what bms to use?pls use diagram to illustrate d connections.

dollarnaira:

Yes
You can do 1000 sef

Wow! Thanks Chief.

Are we saying that they are cells with 3.7v 23Ah rating? How much is one cell please?

jp130:
Are we saying that they are cells with 3.7v 23Ah rating? How much is one cell please?

3.2v

I saw this on Jiji platform though I don't trust this platform. But the cells are expensive for one. Is this reliable or is this cells in jumia or konga?

jp130:
I saw this on Jiji platform though I don't trust this platform. But the cells are expensive for one. Is this reliable or is this cells in jumia or konga?

The seller is here on NL. You can trust him. Please use the number on his Nairaland profile.

cc @Valto

https://nairaland.macsoftware.info/valto

BigDickProblems:


Yeah that’s correct. One side is positive and the opposite side is negative. I was like you too 😁

Those 24cells are all connected in parallels already, meaning that the positive terminals of each cells are welded and connected all together, and the negative terminals are connected all together as well. That is called 24P. Then each of them will be connected in series to form 3 series. This is why it is called 24P3S. And for this to work, you will need a 3S BMS (I.e a BMS for 3 Series connection)

To help further (I don’t know if it’s necessary though. But I love maths😁)Now let’s do a quick maths:
Assuming each cell has a rating of 3.7V and 3.2Ah

The 24 pieces that are all in parallel will give:
= 3.2Ah × 24 = 76.8Ah capacity and 3.7V.

Nb: When you connect in parallel, you increase the capacity (I.e the Amps) but the voltage doesn’t change. This means that the 24 cells in parallel has a constant voltage of 3.7V but Ampere of 76.8Ah in total.

Let’s continue. So now that you have 3 units of 24Parallel cells, it means we have 76.8Ah 3.7V in 3 places. He will go on to connect the 3 of them in series. Let’s do the maths.

that connecting in series increases the voltage but keeps the Ampere constant, so let’s add up the 3 voltages:
3.7V + 3.7V + 3.7V = 11.1V
Total capacity will then be:
11.1V & 76.8Ah
=11.1 × 76.8
= 852.48Wh

But ofcourse, the capacity might not be up to that at the end of the day.

I hope this helps.

Nice one bro, this will really help those who are just ing the thread and interested in the DIY

Binsule:
Good afternoon engineers, pls, I have 2500mAh and 2000mAh lithium ion battery cells that I am gathering to build a 7s pack to attain 24v battery system. Can I mix those capacities together in one 7series pack or Isbit possible for me to build two individual 4s 12v pack of the different mAh capacities to later connect both pack in series to get 24v battery system. And how can I balance that?

Thank u all.

NB:Cells of the same Voltage but different Amparage can only be connected in parallel while cells of the same Amparage but different Voltage can only be connected in series

Use the simple principle of electricity above to achieve your aim

jp130:
I'm in uyo, I know not of anyone. Is jumia reliable? I need 30pcs to try 3s 10p pack

Pls don't buy 18650 cells from Konga or Jumia

billyG:

Nice explanations,now if I have 8 ( 3.2v) Lifepo4 cells,I want to build 25.6v what will d combination called and what bms to use?pls use diagram to illustrate d connections.

Sorry, I forgot to leave a reply.

You have to connect each of them in 8 Series to get 25.6V
Because 8 × 3.2V = 25.6V

that series means constant Ampere but increase in voltage. So if you add up all the voltage of the 8 cells in series, it will give you 25.6V.
Total capacity (let’s assume each cell is 20Ah):
25.6V 20Ah
=512Wh

Since each cells (I.e one cell) are all connected in 8 series, you can call it 8S1P or 1p8S. This means you’ll need an 8S (eight series) BMS.

Just understand that BMS helps manage your connection on each series. So if you create a 10series connection, you’ll need a 10s BMS.

This is a diagram below

I had some challenges with my previous 18650 battery setup. I used 644 cells configured as 92P7S, but it couldn't power my 1HP Sumo pump effectively.

So, I upgraded to 314Ah LiFePO4 batteries — 8 pieces in total, giving me around 8kWh of usable energy. I built the pack using a JK Bluetooth BMS with a 1A active balancer, 4*250w solar s, felicity MPPT.
Batteries and the BMS were sourced from Valto.

I also switched to a 0.5HP Sumo pump, and now I have 24-hour power supply. The Sumo, washing machine and a lot runs smoothly — everything is up and running without issues 24/7.

Intellab:
I had some challenges with my previous 18650 battery setup. I used 644 cells configured as 92P7S, but it couldn't power my 1HP Sumo pump effectively.

So, I upgraded to 314Ah LiFePO4 batteries — 8 pieces in total, giving me around 8kWh of usable energy. I built the pack using a JK Bluetooth BMS with a 1A active balancer, 4*250w solar s, felicity MPPT.
Batteries and the BMS were sourced from Valto.

I also switched to a 0.5HP Sumo pump, and now I have 24-hour power supply. The Sumo, washing machine and a lot runs smoothly — everything is up and running without issues 24/7.

I prefer LifePo4 battery to Li-ion battery for so many reasons:
-they can contain much larger capacity in a small body.
-Their connection is not hectic compared to you welding 644 cells of Li-ion batteries, especially when you can achieve such with just 8 cells of LifePo4 like you did.
-Fire safety
-lasts longer etc.


But Bro can you show us an image of your output (discharge) and input (charge) connections if it possible.

BigDickProblems:

I prefer LifePo4 battery to Li-ion battery for so many reasons:
-they can contain much larger capacity in a small body.
-Their connection is not hectic compared to you welding 644 cells of Li-ion batteries, especially when you can achieve such with just 8 cells of LifePo4 like you did.
-Fire safety
-lasts longer etc.


But Bro can you show us an image of your output (discharge) and input (charge) connections if it possible.

The bolded in theory is not correct. Lion are more energy dense than Lifepo batteries and if the same materials are used to construct them, the Lion will have less weight and give more power.

This is one of the main reasons they were so popular in mobile phones before fast charging led to a lot of them exploding

AndroBlaze:


The bolded in theory is not correct. Lion are more energy dense than Lifepo batteries and if the same materials are used to construct them, the Lion will have less weight and give more power.

This is one of the main reasons they were so popular in mobile phones before fast charging led to a lot of them exploding

Yes it’s true, I know that as well. The statement does not oppose Li-ion, but do you see Li-ion in that high capacity range (20Ah, 23Ah, 50Ah etc) like LifePo4? I guess the answer is no. It’s not common to see them, not like they don’t exist.

This is also obvious in this thread, because a lot builders here uses 3.2Ah or a little above capacity. If there were 20Ah Li-ion cells around, nobody will have that luxury of time to weld 644 cells when you can easily do so with just 8cells. Haba. This is why I said that LifePo4 contains high capacity in small body.