80100 direct cooling


Jake, props to you and Mat

I for one really appreciate the updates

And congrats, I kept wondering if the standard props would work at higher efficiencies since the blade can be thinner in metal than plastic


The design looks great! I’m sure if you went your jet route there would have to be a lot of trial and error to get it efficient, but if your up to it it would be very rewarding. I don’t think you can go wrong with the 80100 direct drive, the most simple solution. Both the 80 and 130KV models work.


Thanks mate!
I agree with the trial and error but luckily I’m doing it as a school project as well as a home project so I have to show my development anyways or I’ll fail :wink:


New test today… I have dataaaaaaaaaa! :slight_smile:
and today I manage to empty the batteries… a bit far from the shore…
changes done to the setup:

new breaker: 171-S1-200-2 : It is an automatic reset, so no more letting water in when it trip. and has a stud connection.
in the end, it didn’t even trip during the whole test.

eLogger V4: I have the 150A version, it didn’t took on fire :slight_smile:

new wing (liquid force impulse): I use that wing to surf, and to kite… it has a ton of lift but is pretty slow… I was curious to try it.
It works great… you can fly very slow, and it handle a bit of speed, turns are smooth…

that’s what I looked like:

and now the interesting part:

I have 2 6s 16Ah batteries
according to the graph I used the full 16Ah… batteries got a bit hot… and stayed warm until I charged them back to storage voltage… they were also very unbalanced…

I played for a good 20 minutes

I’m foiling with around 2.5kW (50A) at 19km/h, and 3.5kw (75A) at 22km/h … it might be due to the wing that flies very slow but doesn’t like much speed in the end… I’ll have to try with a faster wing.

I’m not sure what happened to the battery a bit after 28 minutes to drop like that… all I know is that after that, I had to paddle…
I’m also not sure why the temperature kept rising after that… may be the heat from the battery compartment was slowly getting to the other side… my temp sensor is on the ESC.

I’ll look at the data much closer see if I can see something more interesting…
I did a few try to fly as slow as possible, but I don’t see them here…

one thing for the ones doing the same build:
I have the 80 KV motor, I’m getting up to 3600 rpm in the water, when testing in air, there are spikes at 4600, but that doesn’t seems right…
I’m now wondering if I should go to my backup motor (130kv I think…) or switch to a higher pitch propeller…


Hi Mat,
Very interesting data!

Maybe your propeller is a reason for your inefficiencies, what is the specs of your propeller? It certainly has a different shape than an ordinary boat prop.

I think your power consumption/ride time is similar to mine with the 130kv. With my 40ah 12S when pushing hard I get 30-40 mins and when cruising at 20-25kmh around an hour.

Do you still have sync issues?


If you use the solas 7 1/2 6 I think this prop is not the best in term of efficiency, I have the same and it made my setup really hot with the 80100 100kv also drain the batteries quicker than a 7 1/2 5 aluminium without noticeable top speed change


Good to know, is there a 100KV 80100? how does it go?


no sync issue, I set the timing to 10 I think… only problem I had is when I push my remote to the max, it sets the ESC to 0 … I need to recalibrate it :slight_smile:

propeller is the solas 7 1/2 6 not modified :slight_smile:


yes, that’s the one I’m using… I’ll try to find a few different ones to test :slight_smile:


Nice! maybe the 80KV is more efficient than 130KV, considering we have similar power consumption and you have an inefficient propeller…


Hi Mat,
I was looking to buy the Eagle tree logger, 150Amp today. There is a lot of data and colors on that graph. I want to be able to do that with my set up. Is that what you took the data with? What size wires did the V4 logger 150 AMP version come with? Did you put a temp sensor on anything else other than the ESC. Did you get the GPS sensor?


thank you very much for the data :slight_smile:

i think you use multistar lipo ? i had the same things: they stay hot 1-2 hours after the ride, unbalanced… high IR… then it gets better, best working around 3C, then when i get below 3,8V they became a lot less punching, so i stopped for 10min to let cool and finished them “slowly”, i guess you don’t have this voltage sag with temp with higher quality lipo

for the rpm, well yes that is worried, i suppose you put the right number of pole, on my logger (using hifei) i get the supposed rpm of the KV off load, higher when the propeller goes out when ridding and -27% on load

the solas has to much thrust for its speed, for what i tried it s about the thrust needed for 35km/h, but it is easy to reshape it and to get lower amp (not more speed i think)


yes, that’s what I used… not sure of the wire gage, they’re far smaller than the rest of my wires, but they’re short so I guess it’s fine.
I added a Gps, RPM sensor for brushless, and I had the throttle connected too, but I think I forgot to calibrate it :slight_smile:
For now I have only one temp sensor on the ESC, but I think I’ll add a second one between the batteries and I was planning one for the breaker to understand why it trips, but it seems fine now…

the GPS works quite well, I didn’t look at all the data in details yet… I’d like to total ride length or something like that…


yes, multistar… I’ll look into better ones as I might go for higher capacity anyway :slight_smile:
It’s the first time I push them that hard… the strangest part is that they cool down as soon as you start charging them…

for the RPM, the one in the water make sense… the spike might just be inertia in air or a bad datapoint… I’ll look in detail tomorrow.

to really understand the prop, I’ll fix the full throttle issue on my remote and try it with a faster wing… may be it’s just my slow wing saturating, I never went much faster with the kite with that wing I think…


I have found the metal 7 1/4 x 5 prop to be more efficient than the solas. The top speed is also better with the metal one. The solas was pulling 70 amps and with the metal prop it drops me to 50 amps for the same speed.


@Mat do you have issues with epoxy peeling off your stator poles after a few runs? I can’t seem to make mine stick down for long, I do sand it back to bare metal before applying.


Really cool video! Thanks man!


my epoxy didn’t really covered the very top of the magnets, so I added a layer of “surfboard sealer” I think it’s a very liquid water based polyurethane… and it somehow dissolved think as a couple magnets started rusting.
before last test I sanded everything off to bare metal, and sprayed a polyurethane, it seems to be holding up. It’s regular cheap spray.
After talking with @Vicdes2 , 2K spray might be a better option… that’s where I’ll go if I need upgrade.


metal prop ordered… :slight_smile: not sure yet how I’ll modify it to attach to my motor…


I mounted it the same way as you did with the solas. Ground down to make a flat spot and used the same 2 screw mounting method.