in plain language, how many RPM's a motor will deliver PER VOLT. A 20-volt battery powering a 180-Kv motor will have an unloaded RPM of 3600 (20 X 180 = 3600).
One of the desireable characteristics of powerful RC motors is that they are very small, and they are sometimes found with batteries made of Lithium Polymer (LiPo). These are smallest batteries per a given wattage. They will catch on fire if not managed properly.
10C from 3S4P:
Naming conventions explained. How fast a battery can discharge is it's maximum CURRENT capacity. Current is generally rated in C's for the battery. C is how long it takes to discharge the battery in fractions of an hour. 2C discharges the battery in 1/2 or half an hour. 4C in 1/4 of an hour.
All RC batteries are rated in milli-Amp hours. If a battery is rated at 2000 mAh and you discharge it at 2000mA (or 2 amps, 1 amp = 1000mA) it will be completely discharged in one hour. The C rating of the battery is thus based on its capacity. A 2000mAh cell discharged at 2 amps is being discharged at 1C (2000mA x 1), a 2000mAh cell discharged at 6 amps is being discharged at 3C (2000mA x 3).
All batteries have limitations on how fast they can discharge. Because of this many LiPoly batteries are put in parallel to increase the current discharge capacity of the battery pack. When 2 batteries are wired positive to positive and negative to negative they become like a same-voltage battery with double the current volume discharge capacity.
If you have two 2000mAh cells and you wire them in parallel, then the result is the same as one 4000mAh cell. This 4000mAh cell has the same C rating as the original 2000mAh cells did. Thus if the 2000mAh cells could discharge at a maximum of 5C (or 10-Amps) then the new 4000mAh cell can also discharge at 5C (4000mA x 5) or 20 amps. This method of battery pack building allows us to use LiPoly batteries at higher currents than single cells could produce.
The naming convention that allows you to decipher how many cells are in SERIES and how many are in PARALLEL is the XS/XP method. The number in front of the S represents the number of series cells in the pack so 3S means it's a 3 cell pack. The number in front of P means the number of cells in parallel. So a 3S4P pack of 2100mAh cells has a total of 12 cells inside.
It will have the voltage of any other 3S pack since the number of cells in series determines the voltage. It will have the current handling of 4 times the maximum C rating of the 12 individual cells. So say our 3S4P pack had a maximum discharge of 6C. That means that it has a nominal voltage of 10.8 volts (3 x 3.6V) and a maximum discharge rate of 50.4 Amps (2100mAh x 6C x 4P).
PS I am still learning, I will eagerly edit any mistakes that are pointed out, text copied from RC sites, bits chosen by what I was personally confused about. Corrections may be posted below, or sent directly to email@example.com
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