Battery pack making_Help needed

[pratikdas87]

Dear All,
I am making a battery pack for myself using 18650 cells. I want to make a 3S5P system. my question is can i make 3 blocks of cells each having 5 cells in parallel, and then connect them in series?
normally, people advice to put sells in series first then to connect parallel cells. in my case, although each cell will not be connected to it's next cell in series, each block will be in series with next block. Could you please suggest me if i will face some major issues with my design?

With regards,
Pratik

 

[amberwolf]

Actually most of the time people suggest paralleling first, then seriesing, because of the way BMS's are designed (they monitor a series of parallel groups).

So the way you describe doing it is the normal way it is done.


As long as there is sufficient current path from one group to the next, it works fine.

If all the current has to flow thru parallel interconnects first, to one end or the other, and then go thru a single thin series interconnect, you might have a problem, depending on the current flow you need, and the capability of your interconnects.


There's plenty of 18650 build and idea threads around the forum in the Battery Technology (and other) sections, if you do a search on "18650" in titles of threads and display by topic; most of the results will have relevant info for you, including drawings, diagrams, and images of how people have successfully built such packs.

 

[pratikdas87]

Actually most of the time people suggest paralleling first, then seriesing, because of the way BMS's are designed (they monitor a series of parallel groups).

So the way you describe doing it is the normal way it is done.


As long as there is sufficient current path from one group to the next, it works fine.

If all the current has to flow thru parallel interconnects first, to one end or the other, and then go thru a single thin series interconnect, you might have a problem, depending on the current flow you need, and the capability of your interconnects.


There's plenty of 18650 build and idea threads around the forum in the Battery Technology (and other) sections, if you do a search on "18650" in titles of threads and display by topic; most of the results will have relevant info for you, including drawings, diagrams, and images of how people have successfully built such packs.

Dear amberwolf,
Thank you so much for the information. yes, I am already looking into the 18650 pack threads. there are a lot of information available.

 

[spinningmagnets]

Go to the battery section, and look for the stickie thread index

edit....click here:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=69683#p1051327

 

[pratikdas87]

Go to the battery section, and look for the stickie thread index

edit....click here:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=69683#p1051327

Thank you