you should use 54.6v CC/CV charger because 13s * 4.2v = 54.6v, if your charger output 53.6v it's mean 53.6v / 13 cell = 4.12v fully charge to each cell, whether your charger is CC/CV type or not, cell will be charged up to ~4.1v, but it won't get cell balance if traditional BSM, that's why...