Hi everybody,
As I am currently building a 2nd battery for one of my eFoils, I thought I might share my way of designing and building such a battery pack. Hoping this may help some of the beginners to get into that (sometimes a bit frightening) topic.
First part:
Feel free to share your thoughts and what you would do differently 
Excellent video ! thanks for sharing. I realize that I assembled my Li-Ion cell nickel strip first in parallel then in series like you mention. Do you really think I need to remove restart from zero my pack ? I use nickel 0.2 10mm on 21700 (40T3) on 12S8P.
Don’t worry too much about that, keep it in mind for the next pack
thanks @ludwig_bre I will share my assembly in few days when finalized. Thanks again for your great video.
Good watch. Trying to digest as much as I can before building a battery.
So if I build a 12s battery and just want a single pair of cables and not split it into 2 6s packs what are recommended chargers? Just any of the million 50.4v Chinese chargers? What amperage should I look for? I will run a bms for charging, just not discharging.
A built in bms or a >=12S Charger, like ISDTx16 (not cheap).
So use a 50.4v charger with a BMS?
These questions will be answered in the 2nd video 
But already as a teaser:
Option 1: Build charger yourself from PC/Server PSU and a Step-Up regulator (my way)
Option 2: Buy cheap chinese charger
For both 1 and 2 you need a BMS or at least a balancer, either external or internal.
Option 3: Buy a 12S Balance Charger