Thanks floydRwolf, offgridinthecity, daromer,hbpowerwall, lithiumsolar and many others have large powerwalls. Wolfs build thread is great stressing the inportance of checking IR of each cell. comparing it to data sheets which sometimes don't have the IR listed then you need to go by the chemistry of the cell. Wolf I believe has a list of the different acceptable IR for the different lithium chemistries. really cuts down on testing cells which are bad and which lead to early battery pack failure.