Student Efoil Build - Advice Welcome

[Robby]

Hello Everybody,

I have been doing quite a bit of research on the forum during the last few months. School is out for me in a few days so I figured that now would be the perfect time to actually get started! My list is still incomplete and I would greatly appreciate any suggestions. These are the parts I plan on using, as of now:

Motor: Flipsky 65151 120KV

Esc: Probably Flipsky Seal 300a

Battery: Custom Built - Probably 12s12p Config. Unless suggested otherwise. I am hoping that you guys can tell me what the best website is for buying Lithium-Ion cells in the U.S. I am currently looking at Samsung 30q cells because it looks like that is what a lot of people are using.

Spot Welder: Probably K-Weld unless I can find a cheaper one that is still good quality.

Foil: Still not sure what foil to use. Suggestions?

Remote: Probably just going to end up getting a Maytech unless I can find a cheaper alternative that isn’t too hard to waterproof.

I am currently working on designing my board in Fusion 360. I would prefer to simply get it cut out on a CNC but I’m not sure how much that will cost. I am also in the market for a truly waterproof hatch to safely and securely keep my electronics in.

Safety is a big concern for me, especially when you consider all of the things that COULD go wrong, and I am curious about what everyone is doing to address this issue. I have spent a good amount of time reading different posts in the safety category, but it seems that people all have different opinions on what works/is necessary and what doesn’t. I highly encourage you to respond if you have any comments, questions, ideas, suggestions, etc.

[cmatson]

Robby,

While I haven’t built a complete electric hydrofoil board yet, I am extremely close to posting my build thread with nearly the same specs you are suggesting. I’m also building this as a project in between college semesters!

I’m using the 65151, seal 300a, and a 12s12p (samsung 40T cells). For a foil, I already had a cloud 9 surf foil, but it got their largest wing and I think I’ll definitely want to get one of their smaller offerings in the near future.

[Robby]

Thanks for the quick reply! If u didn’t already have a foil, do you think that u would still choose the Cloud 9? It seems like a lot of people are using Gong foil packages like the Allvator. Would you consider this to be a valid option?

[cmatson]

I had the cloud 9 large wing specifically for foil surfing, so it honestly will be much more lift than I need for an efoil- this will likely lead to more drag, worse efficiency at speed, etc. That’s why I eventually want to order their smaller S24 foil, which is 8 inches narrower than what I have now. For me, spending $249 on a new wing setup for the Cloud9 mast makes the most financial sense.

That being said it’s a stable surf foil, and only time will tell if it makes a good electric hydrofoil, these are just my guesses. If I were to do it over again (or have the budget for an all-new foil) I would probably go with liquid force, slingshot, or gong. Picking the right foil/prop can make a huge difference with your battery life, but it also varies a ton on weight, speeds, and your individual setup.

Whatever route you choose, definitely buy from a company with multiple sizes available in case you want to switch out wings down the road!

[Robby]

What’s up everyone,

After over a year since my last post, I’m nearing the final stretch of my Build . Not being in any real hurry, I have been taking my time and slowly reading up as I progress.

To recap, Here is a list of the parts I ended up going with:

Motor: Flipsky 65161 - 120kv - 12mm threaded

Esc: Flipsky 60v/200a

Battery: Custom 12s12p with Samsung 30q’s

Foil: Gong Allvator V2 X-OVER - Large

Board: Custom shaped and glassed out of EPS foam from Greenlight Surfboards

(Overall a pretty standard set of parts compared to some of the more advanced builds on here, but it’s should turn out clean.)

I went ahead and shaped myself a shortboard last summer just to get used to working with foam and fiberglass. I surf almost daily and I needed a new board anyways.

The board isn’t perfect, but I’m proud of it and it’s pretty good for my first one! The foil board should be much less critical since its basically a big box and it won’t be in contact with the water once I get up on the foil. Here’s a pic of the efoil blank as it sits today…

Just got the foil in yesterday. I order my mast and motor mounts to be 3d printed out of ASA using a printing service. Kinda pricey and I would rather print it myself but my Ender 3 is broken and idk if it could handle printing ASA anyways.

For my Remote I went with the usual Maytech v2. I decided to pick out all the cheap potting they used since it doesn’t do a very good job anyways. I applied one layer of conformal coating on the pcb just for more peace of mind, followed by a thick layer of encapsulating epoxy over the entire thing like @virus did with his remote. Waiting for the silicone for the screen to finish it off.

My goal is to be done with the e-foil by summer. If nothing goes totally wrong I should be done soon . Thanks for reading… I’ll keep posting as I make some more progress!!

[Robby]

Hi! I printed the Gong to Flipsky mast mount but I didn’t realize that the mast on the V2 Gong foil is different from the V1 . Does anyone have the Mast Clamp STL file for Gong Allvator V2 X-Over? Thanks!

[nice2cu]

the aluminum mast?

………….

[Robby]

Yes it’s the aluminum one.

[Robby]

Just shaped my board today! I spent about 6 hours from start to finish. Took a bit but it was definitely a lot faster than my first attempt at a surfboard. Here’s the video of it.

https://youtu.be/fuoW-T5Fmy4

[Robby]

Update - I’ve been making a lot of progress the last couple of days. I started off on the board by routing out the box in the middle for my battery and stuff. I decided to cut all the way through the board and then build a floor that will tie into my box.

This is the best option for me since my board is only 4 inches (about 10 cm) thick. I then built a box to surround my enclosure, all of which will be epoxied and fastened together. All I have left to do is glass the board and finish a bit of soldering and other electronic stuff. I can’t wait to actually take this beast on the water after so long designing and constructing it. Hopefully everything works I made a YouTube video documenting my work incase anyone’s interested in a more in-depth explanation. I’ll link it once its done uploading.

[Robby]

E-Foil Build Part 4 | Building The Hatch Compartment

[Robby]

What’s up everybody! I got busy and I had to take a break from working on the foil until recently. I’ve completely glassed the board and polished it and it’s ready for the electronics to be installed. This is only the second board I’ve glassed so the process came with it’s struggles. The final finish isn’t perfect but I’m super happy with it and ready to move on the the next steps.

I’ve been kinda holding off on the hatch cover as I look for what type of materials to use. I’m debating between some sort of high density foam, and a thicker sheet of plastic. The plastic part would turn out cleaner I think, but it would be much heavier. If anyone has a place to buy foam cores like divinycell in the US, please let me know. I have some experience with fiberglass, but I’ve never laminated with carbon fiber. The final option would be to use a piece of marine grade plywood. I don’t really want to do this, so it’s my backup if everything else fails. I think I have my latch figured out unless anyone has a different suggestion. This is the one I’m looking at: https://www.amazon.com/gp/product/B0015GF2VK/ref=ox_sc_act_title_1?smid=AL09J9CKIG9A&psc=1

My board is quite thin, about 4 inches or 10cm thick, at the thickest point. This will be nice for transportation and storage, but it’s also forced me to become creative on ways to save space. My lid is going to sit on top of the board, instead of being recessed. I may have a lip on the inside of the lid though, that sits a few mm inside of the hatch. This way I can have tighter tolerances and be more successful in waterproofing. I would like my lid to be about 1/4 inch or 6mm, but I don’t know if this will be strong enough. My goal is to have everything on the inside of the board to be waterproof too, but I don’t want to have to rely on this. I will have a 1/4 inch deck pad: https://www.amazon.com/dp/B09C33HSZ4/ref=twister_B09B1NX65J?th=1&psc=1
This will cover the top of the board except for the lid. This will make up for the height of the lid, and help me to maintain a flush appearance still. Here’s another video I made documenting me glassing the board incase anyone is interested.

E-Foil Build Part 6 | Glassing The Board

Thanks guys, let me know if you have any questions. I’m always open to advice.

[diy_efoil_builders]

maybe you can check the guys from efoil holland https://efoil-holland.com/ (if links are not allowed let me know)

I used this for my build, the community is great as well as the manual.

[Robby]

Thanks for letting me know! I’m gonna contact them right now.