Relationship between Motor, Propeller, ESC and Battery

Posted on 29 Nov 2012 by RC-Fever.com  

 

Many of beginners may find difficult to choose the combination of motor, propeller, ESC and battery. If the combination is bad, the component may overheat and cause low efficiency and thrust force.

Motors KV: The rotating speed of motor equal to the multiply of KV and Voltage. For example 1000KV motor powered with 10V power supply. Rotating speed is 1000 x 10 = 10000 revolution per minute. The higher KV value will cause lower torque. Therefore the KV value is highly affect choose of propeller, since larger propeller needs higher torque (lower KV) to rotate.

Battery: The maximum Amp is equal to the multiply of capacity and C, if the battery is 2600mAh 25C, the maximum current is 2.6 x 25 = 65A. If battery operates under the maximum current, the life of battery will be shortening.

Propeller: For propeller, take 1045 as an example, “10” means the diameter and “45” means the pitch. Larger propeller causes larger thrust force and therefore draws higher current.

ESC: The ESC have the specification of current, for example 20A, 30A, 40A etc.

Suggested Combination: 3S battery:

  • 900-1000KV with 9-10 Inch propeller
  • 1200-1400KV with 8-9 Inch propeller
  • 1600-1800KV with 6-7 Inch propeller
  • 2200-2800KV with 5 Inch propeller
  • 3000-3500KV with 4.5 Inch propeller

2S battery:

  • 1300-1500 KV with 9 Inch propeller
  • 1800 KV with 7 Inch propeller
  • 2500-3000 KV with 5 Inch propeller
  • 3200-4000 KV with 4.5 Inch propeller

Above show the combination of battery voltage, propeller and KV of motor, you can use the above information to forecast and predict the others combination. For battery maximum current I suggest to buy a high “C” battery, for ESC itself depends on the size of propeller and the battery. Larger propeller and battery need a higher value of ESC.