km is the same:

**100kv - 10 turns - 1 cross section - 0.1ohm**

60/(2 * pi * 100kv)=0.09549296585513720146133 newton meters torque per motor amp

(4v battery - 0v bemf) / 0.1ohm = 40a motor & battery current at 0rpm

4v * 40a = 160w electrical

40a * 0.09549296585513720146133nm/a = 3.819718634205488058453nm

3.819718634205488058453nm / sqrt(160w electrical) = **0.3019752726269222102173km**

**200kv** - **5 turns - 2 cross section - 0.025ohm**

60/(2 * pi * 200kv)=0.04774648292756860073067 newton meters torque per motor amp

(4v battery - 0v bemf) / 0.025 ohm = 160a motor & battery current at 0rpm

4v * 160a = 640w electrical

160a * 0.04774648292756860073067nm/a = 7.639437268410976116907nm

7.639437268410976116907nm / sqrt(640w electrical) = **0.3019752726269222102173km**

^km (torque per square root of watt) is the same

**1:1 gearing - 10mph ground speed**

**100kv** - **10 turns - 1 cross section - 0.1ohm**

1000rpm = 104.719755 radians per second

(11v battery - 10v bemf) / 0.1ohm = 10a motor/battery current

torque per amp: 60/(2 * pi * KV) = 0.095492nm/a

10a * 0.095492nm/a = 0.95492newton meters torque

11v battery * 10a current = 110w electrical

0.95492newton meters torque * 104.719755 radians per second = 99.99w mechanical

copper loss: 10a * 10a * 0.1ohm = 10w

wheel torque at 10mph @ 110w electrical = 0.95492nm * 1 gear reduction = 0.95 newton meters

**summary: 10mph ground speed, 0.95nm wheel torque,** **99.99w mechanical, 110w electrical, 10w copper loss**

**2.150:1 gearing - 10mph ground speed**

**200kv** **- 5 turns - 2 cross section - 0.025ohm**

2150rpm = 225.14747 radians per second

(11v battery - 10.75v bemf) / 0.025ohm = 10a motor/battery current

torque per amp: 60/(2 * pi * KV) = 0.047746nm/a

10a * 0.047746nm/a = 0.47746 newton meters torque

11v battery * 10a current = 110w electrical

0.47746 newton meters torque * 225.14747 radians per second = 107.49w mechanical

copper loss: 10a * 10a * 0.025ohm = 2.5w

wheel torque at 10mph @ 110w electrical = 0.47746nm * 2.15 gear reduction = 1.02 newton meters

**summary: 10mph ground speed**, **1.02nm wheel torque, 107.5w mechanical, 110w electrical, 2.5w copper loss**

^same ground speed, same voltage battery, same battery current and motor current, different gearing & the higher kv appears more efficientâ€¦ it would seem if the 100kv is at constant speed @ 10mph from the load, with the same ground speed & load the 200kv is still accelerating because there is more torque at the wheelâ€¦