Jezza's Build (slow)


@Jezza: have you add time to take a part the motor ?


Yup I found similar issue with 3D printed parts and thrust bearings, they IMPRINT into the part and if your motor does not have enough play the load gets transferred to motor.

I took out one brass ring inside the motor on shaft side to give some play. this way I just pull the shaft out that little bit during assembly, and when the load builds it can pack in and indent 1mm before load gets transferred to motor, its a simple fix. We are machining our motor mount out of aluminum so it wont be issue with final version, but we will still be removing 1 brass ring to allow us to easily pre-load the shaft on thrust bearing.


You can probably rewind it without much problem, I rewound my out-runner, I would like to see some photos of the inside of that motor, and hear of you observations.


I haven’t, I am on holiday for around 2 weeks so it will have to wait.


Got back in the water today! Got up and going properly for first time. My pod with gear has so much power its silly! I think it will be really fast if I open up to full throttle. The batteries did not love life at all and were a little warm and toastie. ESC was nice and cool and it appears that the water cooling is working without a pump which is great.
Didn’t ride for long, but managed 4 minutes out of a 5000mah pack only rated for 100A constant current (way too little I know but it has tested the working concept).

Now to get a bigger battery!


Hi Jezza,

Awesome, sounds like you’re almost there with it!

I’m going to putting something together soon so no doubt going to be badgering you (and this forum) with questions.

I work as a site engineer for a mining company in Cornwall, so have good knowledge and contacts when it comes to most things engineering. The big area where I lack is 3D printing and CAD!



Cool! We have the same waterproof motor! Excited to hear about your results! I was unable to open mine. The housing is stuck closed with silicone.


I tore mine apart this afternoon. It is not up to the task in its current format. You would need to open it up and fill it with oil to dissipate heat.
I don’t think it is designed correctly for our purpose. I will add pics for you soon…


Here are the pics of the torn apart direct drive motor:

Complete Unit

Internal Housing

Seal Assembly

Rear of Motor

ROASTED windings

I will be salvaging the shaft and most likely the ends of the housing to see if they can be used with my larger 100KV motor which I will epoxy and run with either direct water cooling or oil cooling.


So the motor flansch is most important to cool? Mine will be touching water then.


so it is possible to use a big 63mm outrunner to efoil?


That’s really interesting, thanks Jezza !
So Alien Power went for no cooling at all and an axial dynamic seal (which is why it needs a spring …).
I’ve got 2 6384 motors and I can confirm that the stator gets super hot really easily if no cooling is installed.

Now I’m going for oil cooling, which, in my opinion, is better than having a gearbox + coupling + extra bearing in term of price and friction.


Yeah I think it is possible, just need to perfect the design. I think the best solution would be to epoxy the inside magnets so that they provide no resistance when spinning, and then run the motor in oil.

I have tried to take my 6384 apart, but I cant get the shaft grubscrew off. I think I may need to apply some heat to break the loctite seal.


Yeah using an axial dynamic seal is just a bad idea! Much better to use a double-lipped shaft seal.
I need to get my 6384 apart and get a better shaft on it. I am slightly worried at the thinned wires on the motor though!


Yes, Alien glued it. You can buy it disasembled though, everything comes separated, pretty handy for a DIY assembly.
I think the wires are 12 AWG, it’s a bit too small (only 60 amps max) but I don’t know the max current going through each of the 3 phases…


I don’t think dynamic seals are bad at all. As far as I know, they are the best thing you can get performance and life expectancy wise. But I am keen to hear why you think different.


I prefer dynamic seals if the shaft is not rotating. If the shaft is rotating, I prefer a double lipped seal.
Reason being that I have had less leaks with them.


Im using lip seals, not because they are better, but because they are cheap and easy to replace regularly. Mechanical seals are great if you are careful with installation and they are running in clean water. For my application, I wont trust them in salt water. There is not much I do trust in salt water.


Here’s a cheeky video of some testing… Unfortunately the batteries were screaming at me so I did not want to give it too much gas. I would say this is less that half throttle.

I apologise that the video keeps disappearing, the URL signature keeps expiring!


Can’t seem to see the video mate