I have recently finished my first build - 4ft10 x 20 in with an integrated Axis 19mm alloy mast - I had her in the water several times now and very happy with the performance of the board - having come from Foil Drive the biggest most obvious breakthrough has been smooth touchdowns without that sea anchor at the base of the mast, I would go as far as to say its the single biggest progression I have felt in my riding and has certainly changed the way I approach a wave.
This setup seems to be totally idling at cruise speed - the motor is very quiet - the pod is set at 19cm so I can usually keep th prop in the water but choppy conditions do lead to the odd free spinning event - I am using FD props in a magic hub - Mosfet is around 18 degrees
I have data logged all my sessions and the biggest negative I have found is run time - I am using 12S3P with Molicel P42A and getting roughly 35 mins if the wave riding is OK - this is constant riding with no breaks - by comparison my FD with max battery would get me around 45mins with the standard motor [not the new HP 6384]
The data log says I draw up to 60A battery power on launch and cruise at around 20A
For context the foil I have done most of my sessions on is the Axis Spitfire 1030 and I weigh around 95kg wet.
My question to the group:
Is there any settings in VESC that will give me a better duration - I just did the standard setup and have max power at around 200A and duty cycle at 95%
I was honestly expecting better duration with 12s and an HP motor.
I had a FD Assist Plus and the electronics died so I built my own electronics, I failed until my third build held.
What I first noticed, and this is my third comment reply to this for the week, is that FD use ERPM to limit the speed and this is why run times are reduced when people here compare an FD product to custom build.
FD users also report an impossible 20% improvement in battery time from the HP motor, with maybe a max of 6% from efficiency for the change from the 6374, possibly less overall power needed to get on foil due to it being a quicker process and some general better return from splash downs.
If you donât monitor your speed, you will just keep going faster and use more power due to drag. I usually cruise at 15 to 20 km/h and on my first glassy day I checked my speed and was doing 27 km/h and thought I had problems with my setup as my run was half the normal time.
With my Assist plus setup, it was limited to around 15 km/h which drops as battery voltage drops, and I had the strange experience of the same distance per battery, but could have a shorter or longer run time, due to doing close to the sweet spot of efficiency in speed.
Thank you - the info around FD and the ERPM is super interesting - is this how they deliver their âboostâ updates ? Do you have any idea what ERPM limits they set ?
In terms of speed - im sure it hasnt been getting away on me - im cruising at around 15-18 kph and uber concious to ride efficiently - when my prop breaks the surface it does seem to ramp up to higher revs than my previous FD units have, I wonder if this may be sucking some juice even tho resistance is low ?
It may also be partly the cells - they are an older version Molicel but I just got such a cranking deal on them in good quality pre made packs from a e-skateboard facytory in China that it was hard to go past - the factory finally agreed to make me 12S3P packs with Samsung 50s - I have a pack in transit and it may well resolve the shorter run time.
The next step with batteries is off the shelf 6S1P drone batteries 6 of them wired into 12S3P for travel - the Molicel P45B are perfect as the 6S1P comes in at a cunning 99.8WH - if you travel with batteries you will understand the significance of that !
Their boost is about temp increase in motor amp max, someone stated it is 80 amp, so boost is around 100 amp.
ERPM isnât impacted because the prop doesnât spin fast when getting started, to get on foil for when boost is used. Nothing would happen at speed, as ERPM max would be reached.
The ERPM limit would be for around 15 km/h. Not sure of the number, but based on my setup, my guess would be around 19k - I get around 23 km/h at 23k ERPM at 14s, they are 11s.
I use logs and ChatGpt to monitor batteries and efficiency. Many people here worry about run time, if nothing is hot or smoking, then âit just is what it isâ.
I hope the new batteries work out well. Iâm not happy with my setup, but donât worry and just ride to have fun.
No they dont. They limit the max power and current values. They do this because their vesc and batteries cant handle more than 70A.
They have a custom vesc firmware which allows for a boost at the takeoff amd then scales right back to a low power setting which reduces heat and improves batttery life.
By reducing the max power the motor cant generate to required torque to get to higher speeds and this is why you think they are limiting erpm.
