A little more money but again you get what you pay for. I run two 6000 6S packs in series for my RC airplanes and use a powerlab 8 and parallel board with two 12 volt 47 amp server power supplies in series off a generator. Two deep cycle batteries will not cut it for long charging at the higher rates your looking at.
Chargers and combos
Cellpro PowerLab 8
DYI 24 volt 47 amp power supply
2x HP server PS for 24V - TJinTech