First ever build

efoils – Electric Hydrofoil Surfboards
1

Hello E-Foilers!

Im new here and i did a fair bit of reading already.

First of all i never ridden any foil at all. But i want to learn and also tinker at the same time. I know i know… Building a bicycle while youre learning to ride it etc…

Its all i got around here. I looked at all the waterschools nearby (2-3h Area) and no one offers courses for foiling. Also dont know anybody with a boat that could pull me, nor would they have the patience to stop every 5 meters because i fell off.
We have a big lake nearby that is sailed but the days with good wind are less than 30 a year.
Pumping or foiling from the beach without waves seems really hard to learn from scratch so i rule that out aswell in my area.
So im gonna make due and do what i do best, tinker with engineering and whack something together and make the board be my means of propulsion.

I was reading up alot about VESC’s and motors aswell as looking at commercially available boards/parts. My budget for the whole project should not exceed 1500-2000€ for just the electrical parts and foil. The board is not in this budget since i have all the fiberglass/foam materials laying around already.

The plan right now is to build the board myself so the battery can house like i want it to and i can Adjust the CG in CAD like its supposed to be.

Motors and VESC would be a Flipsky 65161 + 75200 waterproof ESC + flipsky remote (Please Enlighten me if these are good and trustworthy since i read really mixed stuff from a member claiming they are being faked now.
Another Memeber in 2022 claimed the esc and motor combo is choppy and doesnt work at all) I dont want to fork over 600€ and end up with trash that is not watertight or wont work in harmony and breaks in a couple of months.

The foil im looking at was a basic Gong Wingfoil → X-OVER ALU Size L

I never build a board before but i have alot of experience in RC modeling and plastic/composite manufacturing, so fiberglassing is not new to me. I also have access to my own Bambu 3D printer and my job gives me access to CNC machines, Lathes, Lasercutters, Welders etc

For the Battery i was going for Molicel INR21700-P45B Cells.
I found a “good deal” at around 5-6€ per cell so the pure battery cost would be around 700€ for a 13S10P Battery with 45Ah and nearly 2.2 Kwh at nominal.
The battery size needed i literally ripped of the LIFT 4 where i found spec info of 2.1Kwh, i guess thats probably a good starting point. I read on here that foiling itself consumes less than 2kW so that should give me around an hour of runtime (foiling) if im not mistaken. I didnt look further into the voltage drop or performance drop under load of those batteries yet.

I have not looked at BMS Systems or chargers yet so any advice regarding those ill gladly look into it.

Recharging could be only done via a Petrol generator when im at the lake since its around an hour and a half from my place.

There are EV stations tho… Anybody ever tried to make a step down to charge via an EV station through BMS?

Instead of the price of a generator i could also make another battery. Im pretty fit but i dont know how taxing foiling is for my body. If the battery gives me a runtime of an hour that probably will be enought for a day and i dont need to charge it out of home. I could also bring one or two 400W 12V solar panels and trickle charge it when i take a break or drink a beer with my buddies…

TLDR:
New Rider never flew (180cm , 75kg)
No alternative to learning foiling

Setup:
DIY Fiberglass Board
X-OVER ALU L
Flipsky 65161 + 75200 + remote
13S10P INR21700-P45B ~2.1 Kwh Nominal

Thanks ahead of time for anyone answering this post. Excuse my word choice and grammar since i am not a native speaker.

2

An eFoil is not designed for pumping. What you are building is for cruising around on a hydrofoil and having fun, but you won’t be able to use the foil to its full potential.

You’ll likely learn to ride on the foil in your first session. However, keep in mind that this is motorized riding, which is entirely different from non-motorized foiling

3

Sounds feasable. For the battery I have a similar setup, two sets of split batteries 14S11P each. One is built from P42A the other one from P45B. I also have to drive over an hour to get to a lake where efoiling is allowed. 2 batteries gives me 2 times an hour on the foil which is more than enough for me. As a beginner you spend more time on a battery, as you fall, lauch, fall etc. so you will spend more than an hour with a 2kWh battery. The difference of usable capacity between P45B and 42A is marginal, so you could build 2 batteries from P42A to save some money.
Values from my setup, usable capacity 14S11P:
P42A: 2050Wh
45B: 2200Wh

Charged to 4.15V cell voltage, discharged to 3.2V

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5

Thank you for your input. Indeed i save nearly 200€ just by going with the 42A’s.

EDIT: It also seems like the watercooled 75200 is 80€ more expensive than the watercooled 75350. No idea why but i guess ill go with the latter then. Do you even need watercooled VESC’S? If not the Standard 75200 pro V2 would come quite a bit cheaper.

If you dont mind i have some more questions about your setup.

Any reason you chose 14S11P ? What motor ESC Combo are you running and how do you charge your packs?
Do you think 13S10P will provide enought speed with the X-OVER L Wing with 1326cm³ projected, 5.4 AR and 85cm wingspan or should i go with a bigger wing like XL or even XXL?

Thanks!

6

I was expecting that, i wont even try pumping on that setup since with no motor running there will be too much drag. Just efoil cruising sounds alot of fun as is :slight_smile:

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7

In the foiling world down is up and up is down😀
A large wing actually makes you go slower. M or L will be enough, depending on your weight.

8

Should have seen that coming since it drags more haha. Bodyweight is around 75kg so with gear and a vest i guess around 80kg Battery will come out around 10kg and for the board, foil, mast, motor, electronics etc i have no idea yet

9

A few of us are happily running with 10s and the speed is at least 40kmh with the 120kv 65161 and flite prop without guard. I use gong curve L and XL both are excellent.

10

I‘m not familiar with Gong wings but 1300cm2 is definitely big enough for an eFoil. I started with an RL 1150 and 1600 with my first board. With that board (12S) I can foil with a north sonar ha950 as well as a flight flier800cm2 wing. I chose 2x 7S11P because it was the maximum I could fit through my DIYS screw hatch. 13S10P is also a good size, keeps the battery weight a bit lower.

11

The reason is more that you lift out of the water at higher speed with a large wing. Drag is higher but efoiling gives you the pleasure of having enough power accessible if you want it. My first xxl wing had to be pointed downwards to not fly out of the water at higher speed😄

12

Now i get it, thanks.

Keep thinking about a foil wing like an rc plane wing which is still valid but in foiling too much lift can also be an issue as you explained, versus in rc plane flying the sky and your eyesight is the limit :smiley:

Makes sense that a bigger wing could produce to much lift and lift you completely out of the water or has to held down by leaning harder on the nose of the board. I guess the size L will be the sweetspot then. Dont want to break a rib on my first go because it got way to fast :smiley: I can always go with a smaller wing later on.

13

What motor VESC combo are you running? Does a 200A VESC really need to be watercooled or will a passively cooled module be enought with a 6516X Style motor?

14

Have a look at my builds, passive is possible and works but adds some weitgh and is more difficult to build. Some people also put the ESC at the top of the mast like Flightboard and cool it passively through the mast plate and alu mast.

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15

Thank you will do. The placement on the mast sounds promising since i could fab up a plug and play connector into the mast too.

16

Lots of us have used a Fliteboard as a base and then built a VESC on mast - cooling drive unit.

Can’t recall who did the first one but I owe him a beer!! :grinning:

This is an example

This is another one

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17

That looks awesome and really compact but this way the forward/backward adjustment Rails of the mast and board connection is lost. I imagine with my DIY board attempt that could be an issue where i lock myself into a wrong non adjustable position and it could make it unusable or very hard to fly. I cant seem to find a good source about Center of Gravity of a whole board and how far back or forward the connection of the mast and board should be. Maybe a watercooled VESC like the normal 75200 could be better for my first attempt? But the newer non watercooled flipsky 75200 pro V2 has more sensors and is quite a bit cheaper. Still no idea what would be the best choice. Watercooling itself could also uproot some issues like debris in the intake, needs a compact reliable pump, more power consumption etc. I could also try to cool the 75200 V2 passively by making a watertight heatsink plate (Aluminum) that sticks out of the bottom of the board where the VESC mounts to. Lots of ideas at the moment haha

18

I did watercooling on first build. No need for pump - keep it simple.

Intentionally bringing water into the area where battery and/or electronics are present is NOT something I would do again. No disasters but lot of little leaks requiring constant maintenance. PIA!!

If you want to build board just model it after one of the better ones here or measure up a Fliteboard or Lift of the appropriate volume. They have worked out all the dimensions for mastbase placement. IMO the rider adapts their foot placement for each board so the need for adjustable track is debatable.

My two cents for what that worth😉

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19

Im looking at the Lift an Flite boards construction as we speak and i think i will let my build be inspired by the Fliteboard Pro with EDIT: 67L size since im only around 75kg. I really like the idea of having a completely sealed battery compartment and the esc placed on the mast, as you mentioned no PIA with waterleaks or having water and battery mixed in the same compartment. I think ill hit the trigger on the Flipsky 65161 and the 75200 pro V2. Still not sure about the Flipsky VX3 since i read alot of mixed stuff about how its actually not fully waterproof. I know im probably focused really hard on flipsky right now but if it gets me into the sport and is affordable… Dont have the money for an easyfoil kit or flying rodeo kit. I guess ill let my creativity flow and my gut says 75200 V2 will be fine :smiley:

Maytech remotes seem to performing even worse as far as i have seen in reviews.

Felix Remote would probably be golden but it blows my budget.

Ill probably end up buying the VX3, test it. Rip it apart right away and make my own waterproof enclosure for it

20

I have two VX3 and have never had a problem with either (fresh water use) I just bought a third to have a spare.

Have you seen this?

21

My order is already out. But its basically this kit without the prop. Ill go for the Fliteprop.

image
image1424×989 102 KB

Should have gone for the kit to have a spare prop but damn, placed it already :smiley:

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