20Ah, and moreso, 200Ah will be a challenge though, depending on the impedance of the batteries. CN0510 is made for impedances that are around the value of RCAL, which is 50 mOhm. If the impedance is significantly lower, you will need adapt RCAL and to increase the current by adapting Q2,R21.Make sure the voltage swing over RCAL remains equivalent to what it is out of the box. I guess one could go down to 5 mOhm.