Hello everyone, I’d like to make my first battery pack but I have a few questions. I would like to make a 12s4p battery pack with Samsung 30Q cells. I did a lot of research on bms but I did not find any answer to my questions. First of all I would like to connect the bms to balance the charge only but I don’t know the difference in the connections to balance the charge and discharge. I would like to know if you can also advise me bms.
Any help would be much appreciated
Firstly, you should get the wiring diagram from your bms supplier, or maybe the bms will have some clear label that will make it clear.
Here is the basic concept
Okay, thank you. Is this 12s5p battery schematic that I can adapt for a 12s4p battery good? 
And if I balance only the charge, how many amps the bms should have for a 12s4p battery with Samsung 30Q cells?
For the charger? A 12s lion charger with 2a to 4a would be suggest. Maybe the bms supplier would also sell that to you.
No, for example a bms 12s 30a or a bms 12s 100a and is the schematic good ?
The current rating of a BMS is only important when you are drawing current from the battery through the BMS itself. If you wire the battery up so you are drawing current directly from the pack the BMS output current rating doesn’t matter.
This means you can buy a much cheaper BMS, as the lower the current rating the lower the price
Ok thank you, and for the schematic?
looks about right, however, I cant read the labels as your picture res is too low.