Hi Paul -

If your goal is more flight time, you need a battery with larger capacity (mAh). For example, if you switch from a 1800 mAh battery to a 2500 mAh battery, your flight time will increase.

If you were to switch from a 3-cell to a 4-cell battery, you must be careful. Your motor or ESC may not be able to handle the higher voltage of a 4-cell battery. In addition, if you switch from 3 to 4 cells without using a smaller prop, you might exceed the maximum power rating of the motor. In summary, increasing the number of cells requires knowing if your motor and ESC can handle the greater voltage and possibly changing the prop.

Staying with 3 cells and increasing the capacity (mAh) will give you greater flight time without damaging anything. The battery with the higher capacity will probably weigh a bit more than your original battery, so you must be sure your plane can carry the extra weight.

- Jeff