battery charging

I am having a problem with charging my batteries. It is taking more than 15 hours to get it charged up after a flight. Is there a better charger available? I am using the factory supplied charger now.

Buy a balance charger, popular ones seem to the Imax B6AC, try to get an original if you can but 90% seem clones, i have a clone works just fine, charges in about 60-90 mins if that at 5.4 amps