Stuntguy13

As I have been learning about the world of electrics one finds there are lots of ways to skin the cat. One question came up when looking at the A123 battery set up (10.2V at full charge). The initial set up is a AXI 2820-8 motor, this motor has a 1500Kv rating, it can pull over 45amp continuously and is very light 151g, list resistance is 26 mohm. This is the motor I am using now, it is turning an APC-E 11.5 x 4.5 (cut down and repitched 12x6) at 8800 rpm. It pulls the 56oz test ship like a strong modern 40 IC. To get this motor to run at 8800 I had to set the timer motor start/motor end at 24 (48% throttle).
Another motor is also available the AXI 2820-10 which has a Kv rating of 1200 which at 10V would be close to 12000 rpm unloaded that could be throttled to 8800 at say 30 or 60% throttle (only a guess). This motor is also 151g, list resistance is 39 mohm.

A third option is the AXI 2826-8 that has a Kv rating of 1130. The unloaded rpm would be around 11,300 and it could be throttled to 8800 at a timer setting of say 32 or 64%, it is 181g and can pull over 55amp continuously, list resistance is 30 mohm.

The question is given these choices is it better to take a higher Kv rated motor and set it up at a low throttle to run at the desired lower rpm or take the higher Kv rating and run at a higher throttle setting to run at the same rpm for both motors? Which one pulls the lower amps (the mohm for the 2820-8 and 2826-8 are very close 29 vs 30)for the same end rpm?

cncswiss1

if they are all turning the same prop the same rpm with the same input voltage, they are all creating the same output power, so they will have roughly the same amp load. Why roughly the same but not exactly, efficiencys are different for different winds. a watt meter will tell you the diffference in efficiency at that rpm with that prop.


the 28-26 is a larger motor than a 28-20, all things equal it should produce more total max wattage. do you need that extra? more weight as well