A huge thank you to the foil.zone community and especially @JonathanC (sorry for all the questions).
Super excited to ride more and upgrade and build more of these.
I initially wasted many months trying to do FD gen2 style approach once i switched to a waist mounted camden box… so much easier and super quick to put together.
Interested to hear what others thinkmof performance.
I found on a Axis PNG1150 I could cruise on 63% but on a BSC890 it took 84% and the battery drained pretty quickly.
To be fair i am new to this and the board is a huge 125L SUP/Wing board.
Will try a small board tomorrow .
Obviously the BSC was nicer and turned nicely where as the PNG got up easily but was not easy to turn (felt like a balancing exercise)
Noce build. I’m also in the process of building a waist belt assist with a Saite6384 and a small vesc. Will be 12S 2P and optional 3P.
I see you ise an 3Pin XT60 to detatch the motor. I wonder where would be the best place for the connector. Either at the end of the board (where it can be fixed), or just at the waist box? I’ve seen both. I lean towards putting it at the end of the board.
Also what cable lenght (from the end of the board to the box) are you using.
Thanks. I dont think it really matters where. But i suspected it to be better closer to the board (just a hunch… no science behind that).
Re phase length, after a few rides mine is a bit too short. Could do with another foot i reckon. I thought the shorter the better but went too short. It is 1200 from box to connector and 1200 to the motor.
My phase cable is quite thick 10mm outer sheath .
I tried a much smaller board: an old Naish Hover 40L with the smaller foil (BSC890) and it worked really well. I was able to get up on foil and cruise at 71%.
I still think this is too higher power percent for cruising. Can anyone recommend a way to lower this? Maybe a 3 blade prop? Or higher amp ESC/VESC?
Also had a problem… after doing a few laps when i stopped and restarted the motor sounded a but rough and the power cut out at 69%. When back on land it would spin up to 100% out of the water but not in the water. Any suggestions? I cleaned the motor and resprayed with corrosionX and cleaned and regreased the MT60 connectors. The box was dry i side and nothing hot at all.
Any ideas??
Would have thought 2400 is heaps, is that a curly cord?
I just received one from Aliexpress and the guy was very flexible, I messaged him and he added a metre of straight cable to one end of the coiled section very cheaply. The cable is PUR sheath 3 x 2.5mm2 and the OD is 8.6mm
My straight cable version is about 2m total, it’s pretty short but actually found it to be fine when I’m surfing. Have a regular straight leash a smidge shorter so there is spare cable to allow for the leash stretching.
Yeah you are probably right as i am new to this and just not used to such a short leash (when I’m kiting and SUPing i use a 9ft leggy).
Prob just need to get used to this.
That cable looks great. How long is it fully stretched out?
I think my.unit was cutting out (at 69%) prob due to water ingress in my MT60 connectors. Will add epoxy.
Coil stretches to 1m and I added an extra metre. Next time I’ll get a bit added onto both sides of the coil to give more mounting and terminating options. It’s pretty heavy but seems good. I’ve found it’s super easy to nick the cable on the prop with straight cable, hoping the coil section keeps enough tension to prevent that happening.
I use genuine twin blade foil drive props on my own hub.
No idea what current I’m cruising on, both my setups are esc’s, one using XCross 120A and the other one Flycolor 110 HV. Parts bin specials using leftovers!
I do know that the XCross doesn’t really like anything over 2000W so max current would be 50 ampsish battery current.
Can quite easily get up on flat water on my smallest foil which is 880 Fireball, just a bit over 600cm2. 830 Surge is absolute piece of cake and it’s about 720cm2. Skinny long board makes a huge difference with small foils.
I don‘t really cruise on foil as such, basically have the motor as close as practical to my board and simply skim the board over the water barely on foil or else lie on the board and chug back out to wave line. Downwinding I’m pretty much giving the motor a squirt to get on foil and that’s it. 46L 5’5 x 18 board and I’m 67kg.
Thanks.
I made my initial battery packs as 2 x 6S2P instead of 12S2P only because i have 2 old 6S chargers… one of which is dead and the other has issues but charges slowly.
So i need to buy a another charger… the question is 6S or 12S???
I have enough 21700 cells to make another 12S2P pack… and trying to decide whether to just keep 2 x 6S2P pack config or build a 12S2P pack and at some stage change the 6S packs into one 12S pack.
I can see you can get a good 6S charger that can charge 2 packs at a time (HOTA D6 Pro)… or should i go down the 12S route?
I guess 12S is less hassle but 6S better if one pack has a fault.
I dont use BMSs …i rely on the charger to do balancing.
Just double checking this as great care needs to be taken with this aspect of the DIY Assist builds (esp backback). The charger wont balance the battery if you are just connecting an XT90 style connector with no BMS. The OG foil drives do have a BMS but only used in the charging process. Apologies if you are on top of this but worth checking as this is definitely a super high risk area.
Maybe someone can correct me if I have this wrong but on VESC at least I think the throttle % is related to max motor amps. So the 70% might be of 100A or 80A … so if you have max amps set low (Like OG FD+ guessing around 70A) you could be at 80-90% power but still at a reasonable overall current.
I don’t comment here anymore, but just once again just for the insults to build character.
I think the problem that is part of this thread of comments relates to cruising speed. More than the amount of power used. You can’t change the laws of physics and cruise at the same speed using less power by changing power settings.
FD users report slower top speed with the 3 blade prop, as expected. So matching speed and prop pitch will change power required but at a cost. Other posts and comments on this are on the site.
Although the common view here is that Foil Drive limit battery amps to limit top speed, yet somehow still allow more battery amps for getting on foil is an argument I’m not going to engage in.
So I will just state what I did, and if the usual people want to insult me, they can just fuck off.
I used ERPM limit to replicate what my FD Assist Plus did. I set motor amp max to what I need to get on foil, 80 amp. This sets the throttle range. You can also select other parameters for throttle range in VESC tool, others can comment if they have done this.
With an ERPM limit, mine is 23k with 14s, this gives me around 22 km/h top speed which is what I need to push against the wind and swell in the shitty conditions I foil in. The motor amps are around 40 amp from memory at this speed, or for what I think is the issue here, 40/80 or around 50 % of max.
My opinion, is FD do this too. The HP max is around 80 amp max, boost is just over 100 amp for a short time, top speed around 15 km/h with my guess ERPM limiting resulting in around 30 amp to the motor.
Thanks. Yeah i use the balance wires and get my charger to balance the packs.
Actually… on this topic… is it worth adding a BMS? And if so can anyone recommend a make/model for 6S2P pack of Molicel P42A 21700 cells? I have read of people having issues with aliExpress BMSs.
Thanks for this.
Funny… when i asked ChatGPT about percentage throttle and efficiency it replied stating why on earth would i consider throttle percentage when the real question relates to current draw, RPM, prop pitch and size, etc.
So once I replace my ESC with the VESC it sounds like I need to do a deep dive into VESCs (of which i know very little).
Thanks again, i will read about these settings.
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