Is it better to use 2 amp or 6 amp to charge battery?

Well, friend, it really depends on the type of battery you have and how quickly you need it charged. Using a 6 amp charger will charge your battery faster, but it may also generate more heat. On the other hand, a 2 amp charger will be slower but gentler on the battery. Just remember to always follow the manufacturer's recommendations for the best results.