I am lost sorry , you did a water test speed fitted , but then you did the setting on the remote ( so 7 ) , my calculation where done on that using the motor kv and 7 fitted , so between 6 and 7 there is already 15% off and at low speed …
If batt amp and motor are limiting , yes a prop with bigger blades area ( diameter or numbers ) would help
But the way I see things : it is all about rpm drop under load ( if no cavitation ) , we need to stay at the highest rpm that gives that highest speed with the lowest amp
So far I did real water test only with 6 pole pairs settings. Today´s test was just on the bench with 7 pole pairs setting on remote.
Anyway I am going to do water test tomorrow with 7 pole pairs setting, 5% stator saturation compensation and also will try to stick camere at the blade when under full load (will count my fingers afterwards:) to find out if there is cavitation or air getting pulled in as V_S suggested.
Unfortunately atm. I dont have any other prop. Will report back tomorrow. Thanks!
As for your last sentence that is exactly reason why I chose 2-blade prop with low pitch - to get into high rpm and low amp. So far that is not working out.
Have you treated the motor with corosion x?
Did you seal the solder connections or do they just have heatshrink on? If they are not sealed there’s a very good chance that as the power is increasing your motor will lose synch because of shorting underwater.
I sealed my underwater joints with silicone and then put heatshrink over the silicone to guarantee they would never short out. Them I dipped the motor in corossion X.
I tried the 6384 twice and both times got 10kph from it, but my ARC200 was set in the wrong mode, so I suspect it was down to that.I haven’t tried it again as I have multiple units that work a bit better.
I should really do the epoxy thing and treat it properly and try again though!
SUP going without a glitch 8kmph @12A
medium throttle 9kmph @25A
full throttle 9.5kmph @55A
@V_S was obviously right and air is getting pulled in at higher RPM
When I shifted COG forward there was “cavitation” happening much sooner/ atlower RPM (5kmph @20A)
When shifted COG backwards there was much less apparent “cavitation” (prop got deeper) but nose of the board was so high that rear end was whole submerged and it was acting as a massive drag. But still even with such huge underwater brake I managed to reach 9kmph @40A
On VX2 remote I tried changing on pole pairs number between 6 and 7 and there wasn´t any visible difference in behaviour. Upon @Alexandre advice I also changed “wheel diameter” settings to 49mm which resulted in wrong speed data - roughly 4x higher than real speed. Most exact speed reading gave 23mm settings.
So it is obvious to me that I need to move somehow motor much deeper into the water. I hope that extra 10cm will suffice.
The purpose of having this numbers set in your remote is to give you the speed of your motor , not the speed of your board
It refer to the formula used by the remote and the pitch of this prop , so it is important to set the correct number of poles
Of course it will be really different from the gps speed , but the display will show the speed in a perfect world without cavitation drag slip …
So if you get 4x the gps speed , this means that the motor turns well , you get the rpm , vesc isn’t limiting
Just that your prop isn’t pushing water and probably air
49mm is just the pitch of your prop converted to a wheel diameter
After moving motor deeper into the water (some 25cm lower than previously) there was absolutely no air getting close to the prop even on full throttle.
Unfortunately I reached max speed of 11 kmph @21A. Half throttle was around 6 kmph @6A.
So efficiency wise quite big improvement, very quiet ride - no vibrations at higher RPM.
Should I tinker some additional settings in VESC tool?
My current settings are default, just altered:
Motor Current Max: 90A
Battery Current Max: 99A
Absolute Maximum Current: 150A
I am just wondering why after doing new FOC I got motor current only 53A:
and on first FOC done with this motor I got following:
Notice flux linkage difference: 7 vs 2 mWb, resistance 20 vs 15 mOhms
Yet another test ride - this time I made following changes:
upped Motor Current Max: 120A
Invert Motor Direction: True
Changed motor direction in VX2 remote from RW to FW
So result is still the same motor direction but was just wondering it that Rear direction on remote is not somehow limiting something.
I have no clue what settings change really helped nevertheless I managed to reach 16 kmph. And I have to say that when standing this speed is already quite enjoyable.
Manufacturer ratings are max , so pics amp , for how long ? No one knows : 30s , 2 min … and it is in the air
All different in water , so it is a matter of cooling I guess
And it is not because you set 90max on motor that you will get 90A , it depends as well as duty , max batt and the work of the prop
I can report success reaching desired 20 kmph. Upping motor current max to 150A allowed me to draw 77A max (at least that´s the reading on VX2 remote) which gave me 20 kmph.
Really appreciate everybody’s help. Feels like flying, almost And while standing it even brings tiny bit of adrenaline. When riding all my hopes are vested into concom´s preservative abilities to protect my remote precious. I had few dives and so far so good. Just my daughter is increasingly curious what is the function of that tiny empty tip of remote´s water protection
