What do the battery numbers mean?

What do all the numbers on batteries used for RC airplanes mean?

Matt's Reply

There are 3 parameters that define a battery. The voltage, capacity, and C-rating.

The voltage is fairly straight forward. The more voltage a battery has the stronger it is. More voltage means more torque.

Lipo batteries are the most common type of batteries used with RC airplanes today. This is because they can carry the most energy with the least amount of weight. This is good if you're fling an RC airplane!

The nominal voltage of any Lipo cell no matter how large or how small is 3.7 volts. The voltage of a battery pack is determined by how many cells there are and how they are wired.

The number of cells in series is defined by the letter "s". A 3s lipo battery has a nominal voltage of 3 x 3.7 volts which is 11.1 volts. a 4s battery would be 14.8 volts. etc.

The capacity is defined as mAh which is milliamp hours. The capacity of the battery is how much energy it can store. The more the capacity the longer it can last. This means longer flight times. Where voltage increases with the number of cells in
series, capacity increases with the number of cells in parallel.

So two 500 mah batteries in parallel (2p pack) would have a capacity 1000 mah.

All this is explained in great detail on the Lipo Battery Packs page. There are some diagrams on that page as well that will help explain things a little bit better.

The last parameter or battery designation is called the "C" rating. The C rating is multiplied by the capacity of the battery and defines how much current can be safely discharged from the battery.

For example, a 1000 mAh capacity battery with a 20C rating can handle up to a (20 000 milliamp) 20 amp current draw from the motor. Any thing more than that will damage the battery.

I hope this helps. If you have any more questions about what the battery numbers mean feel free to ask!