The amount of flight time also depends on the maintance of the battery. You may want to consider a battery cycler to make sure that your batteries are a peak performance. You can also get a field charger. You also need to know the batteries that you are buying, in that some of the higher capacity ones that are on the market require different charging procedures and time frames as well as charging rates. Even if you change what you have, you still need to maintain them, as we all know a battery can go from good to bad in one flight. Good Luck, Dave