Choise of Brushhless Motor


I had to make the same decision. This is my thinking. I am worried about heat. I want to go with a out-runner motor in a dry pod design. There is very little good news in this whole forum on the dry out-runner subject. There are lots of people going with direct water cooling because it is difficult to cool a out runner any other way. So to keep heat at a minimum.
The lower the KV means, higher voltage, less current=less heat.
If I find that its not as fast as I want, I could increase the voltage to 14S, or hunt around for a higher pitch prop.


Not sure but looks promising.


I would do a direct cooling set up so I’m not as worried about heat! At 14s do you think the 130kv would deliver a better performance than the 80kv? And also what about the availability of commercial propeller? I know higher pitch are harder to find so maybe 130kv is the way to go?


14s and 130kv is approx 6600rpm. I guess cavitation will be an issue.


I am still reluctant to get the 80kv because it seems like the people that bought it are experiencing lower performance compared to the 130kv. Also, on APS’ website, it says that the wire winding is 4D for the 80Kv, 8D for the 130kv, and 14D for the 50kv version. Could this be a mistake? Technically, the 80kv should sit in between 8-14D but it is considerably lower. Is it possible that the 80kv offers a lower performance right out of the box because of its wire winding?


I could manage to efoil with a 63 mm outrunner (tested 90, 100, 120kv) maxed at 27km/h
I think a 80mm is way enough to efoil :wink: the key is to match the propeller


About a year ago I asked the same question about the APS winding numbers, they seem wrong.

One data point, back then I was running the 83110 water cooled 180KV motor. It measured 187.5 KV no load. I decided to rewind it to a lower KV. The wraps were all glued on so I lost count of what was on it. I calculated from the weight of all the wire that there were 4 wraps. They were in a delta configuration. The 3 phase wires that came out of the motor contain 180 strands of wire. So they had 90 wire strands/ wind.
When I rewound the motor I used less strands of a thicker wire. 8 winds ended up giving me 115KV.

Yesterday I counted the strands on my 80100 80 KV motor. There are 130 strands, So there shoud be 65 strands/ wind.


I see! to what would you attribute the lack of performance you are experiencing with the 80kv then?


I never said there was a lack of performance. I don’t know much about the 80KV. I expect it to be good. I have just been working on the pod for it. I have never have run it under load.


Any news on your build?


I pushed it to far. Seding back the stator for rewinding.


What happened? Were you running that 56200? What was your set up?



Have not tired the 56200 yet. I ran the 56115. The prop was to big and I didn’t pay attention to the amps I guess.


Hi guys

I’m very new to this and completely inexperienced in Motors and gearboxes. I’m in germany and we’re trying to build a e-foil for a project at work and I’ve been tasked with getting the motor and gearbox but I don’t know how to pair up the motor with the gearbox. Which ratio should I use? do I pick up the motor first and then the gearbox or the other way around? Please help :frowning_face: Or point me to the thread where I can find the information I’m looking for if you can