Modules per stack: 7 or 8 (the Pylontech product documentation allows 2 - 7; 6 or fewer sits below the HS19 voltage range, Pylontech permits either 7 or 8 to be used with Victron HS19)
Usable voltage range: 650 - 920 V. A 7 module stack discharge floor is 649 V (estimated at 2.9 V/cell).
Capacity: 36 kWh per 7 module stack or 41 kWh per 8 modules stack.