please take into account following things before purchasing any chargers:
-its output voltage
-output current (max)
however sometimes the max output current is not known....just know that to charge a battery, you need to apply an inverse voltage of value greater than the battery output, i.e 7 or 7.5 volts or 6 V battery. The time of charge may vary from charger to charger with same voltage , but different output current values.
in this case, i don't see why the charger wouldn't work...but try not to overcharge your battery pack, you may wanna check the battery's output through a multimeter after a couple of hours to see if its fully charged ..!