# Intro to batteries - Battery capacity and energy available

Updated: Sep 11, 2022

**As we mentioned in our last blog, drone batteries can be purchased in all types of configurations of voltages and capacities. If you can't find what you need, we will engineer a solution for you!**

It is the combination of voltage and capacity that make up the total power of the battery. The ability for the battery to provide current is also a factor, which we will discuss in another blog later. If we multiply the capacity of the battery in amp hours, take mAh and divide it by 1000, and multiply that number by its average (nominal) voltage, you get the lithium batteries watt hours. It is possible to have a battery with a high voltage and low mAh rating, and a low voltage with a high mAh rating that have the exact same amount of energy available. For example, a 6s battery has a nominal (~average) voltage of 22.2V. Say it has a capacity of 5,000mAh. 22.2 * 5 = 111 watt hours. Another battery, say a 3s LiPo may have a nominal voltage of 11.1V and a capacity of 10,000mAh. 11.1 * 10,000 = 111 watt hours. So both batteries have the same energy available!