You can usually check the open circuit output voltage of the charger by measuring across the two output terminals on the charger's connector plug, but be very careful not to short the two terminals together! 
If your charging plug has a central pin and an outer cylindrical collar similar to this:
then I recommend using a short piece of drinking straw over the centre pin to ensure the meter probes cannot touch each other or accidentally short circuit the two contacts together. One probe goes inside the straw (usually the positive probe) and the other goes outside of it.
I realise that this information has come a bit too late to benefit you, but it may prevent others from causing similar problems with their chargers.
I recommend that you place a voltmeter across your battery's output connector and carefully monitor the voltage as the battery approaches the fully charged condition and check if the Green charger light comes on as normal, whilst also verifying that the battery voltage does not exceed 58.4V.
I'm assuming that the battery's
BMS will prevent any overcharging, but if it doesn't, and the voltage does start to noticeably exceed 58.4V
(or the green LED does not light up) then you may want to try using three
(or perhaps more if necessary) 10A diodes connected in series on the positive side of the charging supply:
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The voltage drop across a single diode is typically ~0.6V, so three of the above diodes connected in series should hopefully reduce the 60V output to the correct voltage.
It might be a good idea to modify a standard male to female RCA extension lead by cutting out a small section of the positive lead and soldering the diodes in its place, so that you don't cause further damage to your charger.
Alan
