Building a 3S2P pack with 18650 batteries

[rbchtt]

Hello,
I need some help :

I have 6 Ultrafire 2600mah 18650 protected batteries.
I want to make a 3s2p pack of them.

I wired them in that way (photoshop ):
http://img15.imageshack.us/img15/5479/3s2pultrafire18650prote.jpg


Uploaded with ImageShack.us

Now I need to wire a PCB for balancing.
Where do I get one? \ which one do I need? \ How do I wire it?

and another little question, is that possible to know the final capacity (mah) of the pack above?

 

[Russel]

This might help:

Wiring

Enter the number of cells in series and/or parallel, then check yes for "Show Balancer wire hookup?"

Also, you should resize you image to about 600 x 800 or so. It is excessively large.

 

[rbchtt]

Thanks for the fast reply.
Image resized

Do you have any pcb for recommendation ?
I don;t know which one to buy :\

 

[Russel]

...
Do you have any pcb for recommendation ?
I don;t know which one to buy :\

A printed circuit board?

I use a hobby charger to charge battery packs such as the one you illustrated. Many hobby chargers have a plug on the side that corresponds to the balance lead plug that is usually built into the battery pack. The charger then charges the battery through the discharge leads and bleeds off small amounts of power through the balance leads in order to balance out the voltage of the individual (or in the case of your pack: pairs) of cells.

 

[alpg88]

http://www.batteryspace.com/pcmforli-coli-mn-nibatterypacks.aspx pcb, but i doubt you need it, your cells are protected already.

normally you need charger with ballancer, and i would connect them differently too, like any laptop batteries wired, 2p3s.
2 cells in parallel treated by charger\pcb as one big cell. so you have 3 double cells in series, not 2 strings of 3cells in parallel.

or you could build a holder, and charge them separately if your project allows to remove them.
i build one for my 4d mine are wired just like in your diagram, but i charge cells separately.

 

[rbchtt]

Thank you.
Iv'e seen chargers with balance "socket"
I don;t think that it will be possible in my project.

About charging the batteries separately - yeah, for that I don;t need a pcb,
as I understood.

But what about charging it as one pack??

Ablout 2p3s - I'll get 7.2Volts and not 11.1 - :\ :\ :thinking:


I found this pcb:
http://www.batteryspace.com/pcmwith...lgaugefor111vli-ionbatterypackat10alimit.aspx

Now, the question is whether I need 1 or 2 of them? (it is written for 3s and I have 3s2p)

 

[alpg88]

Ablout 2p3s - I'll get 7.2Volts and not 11.1 - :\ :\ :thinking:


I found this pcb:
http://www.batteryspace.com/pcmwith...lgaugefor111vli-ionbatterypackat10alimit.aspx

Now, the question is whether I need 1 or 2 of them? (it is written for 3s and I have 3s2p)

you'll get 11'1v you got 3 in series.

you could wire 2 cells in parallel, and hook it as 1 cell to the pcb. just like it is done on any 6 cells laptop battery, but i've never seen protected cells wired to another pcb, might get conflict of pcb's.

 

[rbchtt]

just a second.
If I connect batteries in parallel I add the voltage only - no?
and when connecting the batteries in series I add the capacity only ?

I got confused right now :\ can you show me a diagram?

 

[alpg88]

just a second.
If I connect batteries in parallel I add the voltage only - no?
and when connecting the batteries in series I add the capacity only ?

I got confused right now :\ can you show me a diagram?

http://www.allaboutcircuits.com/vol_1/chpt_5/1.html
in series will add v not capacity.
parallel will keep v but add capacity.
2p3s 2 cells in parallel,(double cell) than 3 double cells in series, you will have 3times the voltage 2 times the capacity.
3p2s is wise versa.
3s2p is 3 cells in series, than another string of 3 cells in parallel, you get 3times the voltage 2 times the capacity.

2p3s is the same as 3s2p voltage and capacity wise, but 2p3s is better for balanced charging.