if your charger is not adjustable, you can get a meanwell hlg-xxx-54a led psu, where the xxx is the wattage. i use the hlg-600-54a for 12amp charging of a 14s 40ah pack.
if your charger is only a 2a charger, you can use the hlg-100-54a for about 1.7a, or the hlg-150-54a for about 2.8a max (can adjust downward from there to match the 2a charge if you need to).
the catch with these is there isn't a "switch" for percentage of charge, but just an adjustment pot for voltage, and another for current. so you would need to readjust the voltage pot every time you want to charge to a different percentage of full. if you always just charge to 90%, then you'd put your voltmeter on the psu's output (without battery attached), turn on the psu, and adjsut the voltage pot until it reads a voltage equal to 0.9 x 58.8v, which is 52.92, or 53v. (or if you prefer 4.1v/cell, then use a voltage of 57.4v).
then plug in the battery to the psu's output, and it will begin charging up to that voltage. it will not, however, "shut off" when done like a charger, so you will have to disconnect it when it's done. it wont' continue "charging" (because the voltages are equal at that point) but the voltage will still be present on the output until you disconnect the psu and turn it off.