First, for a good charger, the Accucycle Elite, or the Ice, or the Triton all do just fine and will charge any number of various types of batteries. The Ice and Triton can be set up for either slow or fast charge rates.

As for the Futaba battery, where did you get it from? Was it an authorized Futaba dealer? Did you order the correct battery pack? More specific info is needed.

CGr.