The capacity of the LiPo battery is measured in mAh . mAh basically means the current that you can extract from the battery for one hour.
For example, for a 1000 mAh 3s battery, it takes an hour to fully discharge if a constant 1A current is drawn from it. If the current draw is doubled to 2A, the duration will be halved to 0.5 hours. If you keep pumping 30A, this battery pack can only last for 2 minutes. Increasing battery capacity may increase flight time. In general, it is best to get the highest possible capacity battery. Higher capacity can also provide you with higher discharge current, but the weight will be larger and larger, physical size. The bigger. There is a trade-off between capacity and weight, which affects flight time and aircraft flexibility.
In addition, another factor to consider is the discharge rate. Using a too low discharge rate (C rating) may cause damage to the battery, and the drone's battery is not enough to quickly discharge current to properly power the motor. Since the higher Class C battery is heavier, if you use a battery with a C rating that is too high, you will carry the extra weight , which ultimately reduces flight time.