Eventhough it is sold by Decathlon, it looks like it was developed by Kahe: LINK
It comes with a remote control, charger and clip to mount the remote to your paddle.
It has a protection against running in free air. It spins up, but without sufficient load, it will turn off after a few seconds.
If you unscrew the orange/green lid, you can take out the battery. It is marked as 22.14V 99.6Wh and is connected by a tiny XT30 connector.
If you take it out, there is actually lots of space below it (in total the empty space is 17cm high, the included battery pack only takes up 8cm of that. That made me think if one may be able to use a double-high pack for double range.
So lets start the disassembly. First you need to take of the prop, which is held by a cover-cone, self-locking M4 nut and is in intself screwed onto the motor axle.
The cover cap and M4 nut can be taken off by holding the prop with your fingers. To take off the prop, you need to somehow lock the motor from rotating. The back of the motor is flat, with three holes arranged in a 1" circle. So I printed a small tool, which acceps a 19mm / 3/4" hex spanner.
The motor is a 46mm diameter, 40mm long BLDC motor. ESC and remote module seem to be integrated on a double-stacked PCB. Cooling is done via the cooling-stub.
Inside the case, there is a ball bearing and shaft seal (“Simmerring”) to support and seal the main shaft. The cooling stub is sealed via a O-Ring.
Lastly here some details about the battery pack: It consists out of 6S1P LG INR21700-M50LT. They have 4930mAh and 14.4A max current. That would result in 109Wh and 320W.
The battery pack includes a BMS with current measurement and a temperature sensor.
Will try this thing tomorrow on the water. Waiting for good ideas how to tune this baby Maybe put my own ESC in there and the double-stacked battery for 600W instead of the max. 150W
Thanks for that ! I was trying to find some info with no luck to build my own and have some fun without spending 2k€+ on a Scubajet like thruster with probably similar specs…
What’s the material made of around where the motor is housed ? I would guess it’s non metal ?
I have two eFoils, so if I want to be fast on the water, I take those
So I am just looking for more runtime.
I also like that adapter they sell (or will sell), which turns it into a dive scooter. Definitely will try and print / build my own version of that!
Also, I think, the motor will easily deliver more power, but the ESC may be the limiting factor. But with will, one could certainly turn this assist into a high speed torpedo
Received my 12x M58 cells today. This gives me now 250Wh compared to 100Wh original, so about 2.5x the range.
Also finished the housing / cell spacers.
Next up: Spotwelds and BMS
The build is finished!
As can be seen on the next images, I used 0.2mm Nickel to join the middle of the pack in series. With that done, the two halves are folded upon each other, with a 3D printed spacer to keep some distance and allow the balance wires to pass outside. (I used silicone wire first, as I did not want the balance connector dangling around already. I joined that connector to the silicone wires later)
On top and bottom, the parallel groups are joined first and then put in series by another nickel strip. Note: For a high-current pack, you would do the series stips first, as they need to carry the current, then the parallel strips, which only carry equaliztaion currents. This pack will see 10A max., so 0.2mm Nickel will be overkill anyways, thats why I decided to go with parallel first, as this is easier to assemble.
Then the balance connector is attached, followed by the main pack connection to the BMS, which is heatshrunk afterwards. Lastly the B+ connection to the XT30 connector. All fits well into the housing and can be capped off.
Hello,
thank you for sharing these photos,
I would like to work on a similar project.
The battery is that of my bike, a bosh power tube 500w of 42v.
Could you help me find the motor and ESC from hobbyking compatible?
I think it’s quite easy to make, with a PVC tube, and 3D printer…
Hey @ludwig_bre , amazing job! Looking really great! I was planning to do the exact same project myself. Did you use ABS or PLA? Are you willing to share the STL file?
Many thanks!
Hello Ludwig, I’m going to start the same project as your to increase the runtime of my Kahe pod. Could you please tell me if it works and if the battery you designed replied to your needs ? Did you have any issues ? Many thanks
As long as they are at the same charge level (voltage) when you connect that should not be a problem. But I doubt you find enough space for both batteries + the connectors
