I like that guys' videos, i had not seen that one yet, good stuff.
Doing what he did for a 48v 200ah lifepo4 battery would be very cost prohibitive, a much easier, faster option would have been to buy 8x 100ah 12 LIFePo4 batteries and gang them up, they already have a BMS and are rated for higher peak current draws. for example, the so called mighty max on amazon has 12v 100ah batteries, 8 of which would recreate what i have here with much less effort, at $30/ah/48v. the other option would have been the 30x of the 3.2v 100ah brick cells at $23/ah/48v. this setup i'm working on should be $9/ah/48v, but its so much more work. lead acid is cheaper up front, i learned, but has 1/3 the life, so it ends up costing 2x as much if the time period is long enough.
avoiding imported parts is a nice goal, my leaf was made in asia, so i'm not off to a good start, right. In general its very hard to find the exact part domestically made at all, let alone for a competitive price. often I give the imports a shot, and if they don't work go premium on that item. there are many layers of protection to get refunds on imported parts that fail, esspecally from good market places like amazon, and as a last resort, credit card charge backs.