Hi,
I want to use the Mini V6.8 ESC from flipsky (Software Version 5.02) together with a 6384 motor for foil assist.
The problem:
When using current mode, the motor spins up to max RPM at low throttle when in air.
In duty cycle mode the control behavior is better. But there is a small brake current when the throttle is in neutral (about 0.1A).
I don’t like both behaviors.
Duty cycle control with no brake current would be nice but I did not found a solution for this.
How did You solved this problem for VESC in foil assit mode?
Also that is normal and can not really be changed.
In your case current control will be the best option, as said in water (under load) it will work fine. You can limit ERPM to prevent the motor spinning to crazy high RPM in air.
It performs great. With 12S I have more power than enough. No problems with heat or current (I use the FD three blade prop - black).
But for foil assist mode use duty cycle control. Current control may work for E foils and skateboards but is not nice for foil assist (when the prop has sometimes no load).
I’m interested to know what runtime are you getting and what pack size/Wh? I find on a 12S2P (p42A = 372Wh) pack I’m getting only 16 minutes… and that includes catching a few waves. To be fair this pack has had a lot of use and the cells heat up - I am about to build a new pack (12S2P) using RS50 cells which can handle more current so shouldnt heat up so should give more runtime before sagging (also at 5A/cell that’s 432Wh).
I’m curious as I am running the same ESC and the Flipsky water proof 6484… but using my own printed (UV/SLA) 3-blade folding prop. I am 81kg using Surge 1010 foil.
Sorry I don’t have exact runtime data. But my cells (Molicell P45B in 2P or 3P) stay cool. (OK water temperature in the north of Germany is rather cool too).
The prop makes a huge difference. The FD three blade prop is great. Since I use it I had no more problems with heat. I feel also a huge difference when the prop is at the water surface. It still has good grip/thrust when half out of the water.
Thanks, I’ve used a friends FD assist max a few times… I really didn’t like it… a lot less power than mine… not sure if thats down to ESC detuning, prop or FD’s 11S vs my 12S battery. However, he gets way more runtime… so I guess that is really the better option… something I’m trying to figure out how to do (other than simply more battery).
If you can get up with less power, why do you prefer having more available?
If you use more power than actually needed, you will use up run time for no real gain. I have limited power output in VESC to 2kw and that has significantly increased my run time.
yeah its a good question… as I know it sounds contradictory. But I find riding with more power makes everything seem that much easier… but yet I would prefer, given the choice, to have longer run time.
Thats a great idea. Which setting does that. I think my Motor Current Max is set to 90 and Battery Current Max 99A (both set to Amps but I note you mentioned Watts - or was that just the conversion) Or is there another setting (I am completely new to VESC’s).
Thanks
That is much better than limit phase current , since the VESC will then compensate voltage sag with higher current and keep power output the same as long as possible.
Motor current limit should most likely be significantly higher then battery current limit.
The motor (together with driver) will act lile a so called “buck converter”. So motor current be so much higher then battery current as duty cycle is lower then 1. Practically the power in (from battery) is approximately power out (into motor), but duty cycle is the percentage of battery voltage applied to motor.
Duty cycle is capped around 0.95, but at low rpm will be lower. Therefore motor current becomes way higher then battery current to maintain approx power in → power out.
In practice motor current limit will give a torque limit. Battery current limit closer to power limit but will not compensate for changes is battey voltage. Power limit does that as well.
Depending on many factors, but motor current limit 2-3 times higher then battery current limit is often resonable higher battery current limit then motor current limit is most often not suitible.
I am facing an issue with the FS ESC v6.8… after the first session which worked great, it is now limiting thrust to 40% (my very rough estimate) - but basically the motor sounds the same and I get no more thrust from about 40% throttle all the way up to 100% throttle (as read on the remote).
As it worked on the first session I suspect an issue with the phase cable or possibly my battery cable (I use a Y-harness to join 2 x 6S2P packs). I dont think its the battery side as I have tried a brand new pack and there is no voltage sag.
The VESC tool says its delivering around 1.5kW which is prob correct - as I’ve read we need around 2kW to get on foil. there are no VESC faults and no excess heat in the box. But not sure why it cannot deliver more than 1.5kW.
I will replace the whole phase side of things again (3rd time in a month - bugger!)
I have had phase cables deteriorate (break at flex points) but they show up as a jittering motor - where as this is running smoothly/fine… just under powered.
I have the Max Motor Current set to 90A and Battery max current at 99A.
I tried changing the Max Motor Current to 100A and it moved up to 1.68kW - but thats still way more underpowered than my first session I suspect and it was on 90A when I did that first session so shouldnt have to change this.
Sorry for posting this info around several.posts but feel i need to clarify the issues i was having with that ESC and how to resolve…
In short i fixed the problem of the FSESC v6.8 being overloaded by replacing my 3d printed props with FD 3 blade props. Now runs very well and gives 30% more runtime!