Author Topic: Im confused about charging 3s4p  (Read 1148 times)

0 Members and 1 Guest are viewing this topic.

Offline EhazeTopic starter

  • Contributor
  • Posts: 43
  • Country: us
Im confused about charging 3s4p
« on: November 28, 2021, 04:26:20 pm »
So if I put 4 cells in parallel , and then 3 of those in series. Made up of  18650 cells , to get 12ish volts .
           I want to charge that  from a wall outlet . So I have some drone stuff and I found an Iflight M4ac balance charger 1-4s .
     Can that take the place of a BMS , or will I have to find a BMS and balance cable , and or still use the iflight charger to display the 4ps?
   How does the BMS or Iflight know each of the 4 Ps  is balanced ? Will  each one see them as one cell if in parallel.

Sorry this gets confusing for me . Youtube videos show me how to build it but I am learning the rest through asking question about what is correct .

 Also if I have 1 group of 4 18650 cells in parallel , do i need a balance wire for each cell or just 1 for the pack ?
« Last Edit: November 28, 2021, 04:43:39 pm by Ehaze »
 

Offline sleemanj

  • Super Contributor
  • ***
  • Posts: 3079
  • Country: nz
  • Professional tightwad.
    • The electronics hobby components I sell.
Re: Im confused about charging 3s4p
« Reply #1 on: November 28, 2021, 08:58:48 pm »
Parallel cells are effectively balanced by definition (but only connect cells in parallel when they are already the same voltage).  Balancing is in regards to series cells only.

A "BMS" monitors cells during discharge (and charge) to ensure that they do not get too-high voltage, too-low voltage, or too-high current. 

Since you do not have your battery charger connected when you are discharging the cells, you should have a "BMS" or "Protection" board to do that built onto the pack preferably.

Your charger is capable of balancing the cells, sometimes a BMS board is capable of that also, you need to examine the capabilities of the BMS.
~~~
EEVBlog Members - get yourself 10% discount off all my electronic components for sale just use the Buy Direct links and use Coupon Code "eevblog" during checkout.  Shipping from New Zealand, international orders welcome :-)
 

Offline EhazeTopic starter

  • Contributor
  • Posts: 43
  • Country: us
Re: Im confused about charging 3s4p
« Reply #2 on: November 30, 2021, 02:42:44 am »
ok so I think  I still need to wire in the balance lead so the charger can see the 3Ps , The charger uses a xt30 and jst connector , so i guess its just like charging my drone batteries ? I still need a bms board as a protection device , but i cannot find one that is clearly a good product , Amazon is no help , they have many but where do people get reliable products from ?
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf