BMS Charging Help

Okay my build is going to be 4x3s 5000 mah 20c batteries 192kv motor Vesc from proto-boards (the idea atleast) 15/36 gearing. But the important thing for this topic is probably the batteries.

REAL QUESTION DOWN HERE! As of my understanding bms can be used for easier charging. What i think atleast. But my problem is since many BMS systems is pretty expensive if im going to get the discharge too. So off course a 12s BMS but how many Ampere?

And another question the charger? does it have to be a 50v charger or is it possible to use an old laptop charger? And what type of chargeing port is suitable for this task?

And last question. If im not using discharge i probably wont have the ability to use the on/off on the bms. I know most people use an anti-spark plug but. I could then use vedders button thingy, make my own mosfet or use a breaker or what they are called.

All feedback is appreciated :smiley: