Without getting too technical and talking about lossed or absorption charge voltage.
10kWh charge into each battery is 208Ah (kWh / battery voltage x 1000) or (10/48 x 1000)
Lets round this off to 200A and divide it by 4 hours (200 / 4 = 50)
This would equate to a AC charger with an output of 48V 50A.
This is basic maths in its simplis’t form taking everything was equal, with what comes out of the charger goes into the battery without losses.
