Colorado winter build - ARC200 - flipsky 120kv - samsung 30q

Just beginning to order parts to do this build over the winter. Figured by the time everything comes in the lakes are going to start to freeze :smiley: If not, I got a drysuit!

Here is what I’m looking at.

Motor: Flipsky 120kv FS65161 - Efoil motor FS65161 100KV 6000W 20S water proof for motorized surfboard | – FLIPSKY

ARC200: Looks like some people had luck without watercooling this esc?

Battery: Either 12s12p or 12s14p of samsung inr 18650 30q. Any other better battery choice? I saw a few people with 14s batteries, but the ESC above look like 12s max. No BMS, built as 2 6s12p pack and charge with my RC charger that can put out 750W.

Looks like the cheapest is shipped form to the US. For ~$3 after shipping: Samsung INR18650-30Q 3000mAh - 15A - 18650 - Li-ion - Rechargeable batteries | NKON

Spot welder: MiniSpotA - MiniSpotA spot welder | Endless Sphere DIY EV Forum

Prop: Probably 3d print or see if I can get the FR one here: Fr 2019 motor system - #229 by Alexandre - Propulsion System (Motor, Gears) -

Foil: I have a slinghost fkite with space skate 65cm wing for kiting. I’ll buy extra 90cm mast so I can swap between kiting and efoiling. Or I have a liquid force happyfoil. If I can find a big wing (Impulse wing?) for that, I might try that instead.

Board: Either a old windsurf board or a considering cutting one out of foam and fiberglassing. Might use a pelican case for the first try for waterproofing ESC/batteries.

Mast clamp: 3d print


Use a big heatsink if you want to do this, and make sure you set the temperature cutoff.

Not sure if anyone has had success with this yet. I’m also not sure what cooling it needs.

Other options for the ESC, depending on where you are would be: A200S V4.1 - TeamTriforceUK

Battery will depend on the ESC. If your ESC can handle 14S, then go for 14S12P.

That welder looks very interesting. I bought another DIY version that was a bit more expensive.

I also have the space skate wing, but haven’t tested it yet as I have been riding the Gamma 68 wing instead.

If you build your own board, then make it nice and compact. 5ft x 62cm x 12cm is a good size.

@Jezza Yeah I’m leaning to the ARC200. But I’ll hold off on deciding that because the motor is probably the long pull in the project.

Looks like enough people are having success with that motor, so I think I’ll order it! Probably 120kv since I’ll be at 12s?

You’re in the US so the ARC200 is a no-brainer! Their after-sales service is amazing compared to the other companies as well.

Definitely go for the 120KV motor. If I hadn’t bought I’d try convince them to custom wind me a 140Kv version. But a custom wind would definitely take longer to get it as they will need to test etc.

Got the Arc200, flipsky 120kv, samsung batteries, and spot welder on order! Now the long wait for stuff to get delivered…

IMG_20191002_201031 IMG_20191003_154020 IMG_20191003_203101

Got the batteries and drew up a 6s12p holder for it. Going to have two of those and charge with my big hobby charger.

Here is the 18650 holder if anyone is interested:

Also was testing out the miniSpotA spot welder. That looks like it will work great.

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I ended up modding @ YAHEF mast clamp for a slingshot mast

Got a couple 100mm m4 screws on the way to fasten everything together.

Next gotta drill the mast and run the wires up!!


Hi! I also use the stl from @YAHEF. He did a great job providing this, many thanks. I printed with 0 infill and try to fill with epoxy; from printing quality (PETG) I am very happy about the result. I have a gong mast which was easily to adapt to the stl. Basically it should look like this from the inside:

Final product (still hollow) is this:

I used wall 6lines outer wall, it seems to be dense. Next step for me would also be to drill the mast…

Cheerio, Jan


For some reasons, your spot welding test video doesn’t work. This one worked for me:

Which spot welder is that ?

I am trying it with a small amount of gyroid infill and no bottom layers. What what it looks like pouring epoxy should be able to flow throughout the part, and maybe will give me a little PLA fiber reinforcement…

Not sure why the video didn’t work for you. I just meant to post a link to the google photo video link because that is a lot easier then uploading to youtube for a short video. Apparently the forum software is smart enough to try and make it playable on the post.

The welder is a miniSpotA from here: MiniSpotA spot welder | Endless Sphere DIY EV Forum

Pretty cool little device. Not a kit and don’t need to buy anything else if you have a big 3s lipo. Korean guy designed them and builds them up. $70, but after shipping to the US and some international fees it was about $90.

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I drilled two holes, one for injection via syringe and one for over pressure release. First I also had without top or bottom layer, but it actually looks quite nice when print is closed.

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Yeah that is a good idea, just like pouring a casting. I’ll try and reprint with the bottom layers on and maybe add the holes to the stl.

Use an epoxy with low exothermic reaction or it might heat up easily up to the point PLA soften

Yeah true, I’ve had a plastic cup get pretty distorted when I left some epoxy in there.

I’ll try and pour the stuff I have out in garage when it is cold out and that should slow down the reaction quite a bit.

Made some progress! Also got to try a lift efoil yesterday! Got up and riding pretty quick, I think those kiting foil skills really help out.

After already done with most of the spot welding, decided a different layout probably would have been a bit better for max current draw, but this should do for now. Looking at 10awg wire from the batteries to the esc with xt90s since that is what the ARC200 has already.

Had to use a little steel wire to fish the large 8awg wire the motor came with through the mast. Hopefully can get away with passive cooling the ESC! Or maybe mount the ESC to a plate of aluminum that is exposed to the bottom of the board or in contact with the mast.

Are people epoxying the mast holes so they don’t fill with water?


Batteries are ready to go! Working on getting the CNC back up and running to cut a board out. Hope to have something by spring…

Testing charging with the new 24V 71A power supply and the icharger 406:

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You can do water cooling up the small hole in the forward part of the slingshot mast

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Hi Bryce!
Love your setup and it’s an inspiration for my eventual build.
I was looking at the Flipsky drawing and it looks like m5 screws - is that what you meant?

Also curious how your build is going.

Hey @Adfrank , Yes your right. I actually ordered the wrong ones and reordered m5 screws

Build is pretty well, but on hold for a bit because I’m working on rebuilding my CNC machine so I can cut out some boards.

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