Jsonnett's Latest East Coast Build

Ahoy guys!

@pacificmeister’s build videos first inspired me to start a build of my own and I have been tinkering with these boards for almost 3 years now. This forum and community have been a massive help and an incredible resource. Since the start, Ive spent hundreds of hours burning up motors and ESC’s, rolling through spool after spool of printer filament, and crying myself to sleep after countless frustrations (just kidding…kinda). This project is not for the faint of heart although with the release of some key components over the last year or so, building your own efoil is starting to get alot easier for the intermediate to advanced DIYer (I’m talking about some key enablers like the maytech remote and purpose-built motors like the flipsky). Sure the 80100 can work great (I’ve worked with 4 different alien motors) but having something purpose-built right out of the box is a step in the right direction and a welcome break from the usual routine of bathing parts in epoxy and swapping rusted or sandy bearings as a regular maintenance item. Not that there isn’t still some waterproofing left to be done ;).

Even using these components there are still a few basic rules for the first time builder that must be adhered to STRICTLY. These are things I learned the hard/ expensive way and that anyone with a successful build on here can stand behind.

  1. If you “think” its waterproof enough… ITS NOT. Ask me how I know and how many failures it took me to learn this lesson. Build your waterproofing like the board needs to be dropped out of a helicopter into the salty depths and then remain underwater for a week while guarding your high voltage, water-soluble, college fund. Wondering if you need to stop riding to make sure your gear is dry sure takes the enjoyment out of the ride. All that said, try and design in some type of backup plan in case you still managed to underestimate water’s motivation to make all things dry, not dry. In my case, the chassis of my electronics rack elevates all of the water sensitive gear a few inches above the bottom of my battery box. The bottom is also lined with a super absorbent chamois to soak up and water that might make it in and keep it from sloshing around. Allow wires or cooling tubes the ability to get tugged on, banged around or flex without risking the integrity of the seal.

  2. Build EVERYTHING in the power system with the ability to handle WAY more current than you think you will need. Begin this equation with the motor you select (typically in the 5 to 8KW range). Now follow the future wiring up the electrical circuit to the next component, likely the ESC. I would make sure your ESC is rated for at least DOUBLE the rated motor current. In the case of a 7000W motor running 12S (50V) that’s 140A. Get an ESC that is at least 300A. You can go cheap like I did but I will the first to tell you that one 400A ESC is cheaper than two (or in my case 4) lower current ESCs. The same safety factor goes for wires and batteries. Make sure your batteries are rated to drive the motor at its full current rating without breaking a sweat (batteries like to get really warm when under heavy load and squeezed into a small waterproof box). Settle for nothing smaller than 8AWG wire anywhere that will carry motor current. Battery analyzers/voltmeters are a must in your system to measure current flow and battery voltage. I burnt up both a 150A and 200A cheap amazon version using a motor that should not have pulled more than 120A. A hall effect style vs. shunt resistor is nice because it does not get hot and if it fails wont leave you stranded. Both my shunt style meter got so hot that the actual shunt desoldered from the circuit board (multiple times). Also spend considerable time thnking of how you will keep things like the esc, motor or maybe even batteries cool. Heat doesnt have anywhere to go inside a waterproof box unless you give it a path out.

  3. Overbuild everything. Like the electrical system, efoils are a demanding application and if your board works it is seeing lots of power and stress. Weight is important so dont get too carried away but remember if it’s between an extra 1/2 pound of reinforcement or your mast getting ripped off, you can always save the cheeseburger for after your ride.

  4. Cheap is actually expensive (mind-blowing, I know)Buying an oversized ESC that you know will handle your current loads easily is ABSOLUTELY worth the extra cost. If you don’t have enough money for the better component, wait till you do. Don’t buy the cheap stuff. It will save you so much money in the long run. I probably have $1200 in my current setup but have spent double that of the pile of black, stinky motors and controllers and other parts in my trashcan.

I have tried 5 different motor setups and concepts up to now and this is the first one that I feel pretty good about. Here is my setup:

-Reshaped standup paddleboard cut down to a 5"6". Pacificmeister style recessed battery box.
-Andersson Foil. I think the model is called the magic carpet. IDK it was really cheap on ebay a couple years ago. Totally flat garolite foils and one piece aluminum mast and fuselage. Surprisingly seems to work pretty well (see below)
-Flipsky 65151 120kv motor half-filled with corrosionx
-Flier 400A ESC (Awesome customer support but sadly I cannot recommend with this motor. Get the flipsky or swordfish or even better the vesc if you have the budget)
-2x Turnigy multistar 6s 20000mah lipo batteries (series 12S)
-Maytech V2 remote
-Turnigy dual output BEC 5v and 12v (for cooling pump)

  • cheap 12v centrifugal water pump
  • closed loop cooling with heat exchangers made from PC cooling blocks bonded to heatsinks. Radiator mounted through bottom of the board.
  • Amazon hall effect style voltage analyzer/ current meter with color display.
    -Solas prop
    -harbor freight “apache” waterproof case

I have ridden it 4 times now with success. It has plenty of power and throttle response is very smooth and predictable. The foil took a little shimming to get right but now it feels pretty spot on. I dont have any speed data but I’d imagine I can get up on the foil around 8-10 mph and a top speed around 18mph or so. When up at a comfortable cruising speed (maybe 12ish mph) I am pulling about 47-52 amps which I am really pleased with. Id like to figure out how to get more runtime out of it. Currently, I am only getting like 15-20 minutes of ride time. Once I get down to about 44V, the motor starts having weird sync issues and runs really rough above 30% throttle (i think i blame the FLier ESC). Not enough to get up on the foil but at least enough to ride on my stomach back in. I have my LVC settings on the ESC at 3.3 v per cell and 40% power. I think that might be what’s causing this so I may try the soft cutoff feature to see if that fixes it. If it is the LVC causing this behavior I might try running a lower cutoff voltage to see if I can get closer to around 40V before the cutoff. I also sometimes have sort of odd motor startup behavior but it usually doesn’t cause any problems. Other than this everything else seems to be working well (knock on wood). I think if I were to start this build over, I would not go with the Flier ESC as it doesnt seem to work super great with the flipsky motor. I may try the flipsky esc in the future.


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Here are some videos I took. I even took it out in some small surf in the second video! So much fun!

Have fun with your builds! The ride is so much sweeter when you earn it.

8 Likes

Great Advice @Jsonnett

Looks like me holding off a year might have saved me some of the headaches.

I hope you get the issues ironed out on low voltage.
Ive opted for the Flipsky 65151 120kv along with their Seal 300A ESC. (unsure how spalsh proof this is but im expecting to need a box for it)

I would like to know if any data like temps or RPM can be sent to the maytech v2 remote with the Seal 300A

Im also wondering if you can configure the remote like the lift foils where you can just nail the throttle 100% while getting up and then cycle through modes to increase speed. I imagine holding the throttle accurately while trying to get up could be a challenge. The documentation on both the Seal 300A and maytech remote is a little sketchy from what i have seen.

Your build looks really pro, You should be proud.

You can only send battery voltage (through a low res bar graph thing) and motor RPM back to the remote. RPM is easy. you just tie the RPM sensor wire on the receiver to one of the motor leads.

The Maytech remote does have a cruise control feature but no power limiter like the lift foil. Im not sure you would want that though as being able to modulate the throttle really helps you stay balanced. I find that I am almost constantly adjusting throttle to maintain level flight in addition to moving weight off or onto my back foot. I have ridden the lift foil as well and the power limiter is still pretty fast even at a low setting and I didnt ever feel the urge to just hold it wide open since throttle input can really help balance.

I was down in North Carolina for Xmas. Nice to hear some one else here in the eastern US is a builder. Its warmer there than New York.

1 Like

Hi.

Your build looks great!

I thought I saw that you already shared the prop faring (motor to prop hub adapter), but I can’t find it.

Do you mind posting the STL? My Chinese prop will be arriving soon.

Thank you!

:call_me_hand:

Sure Thing.

https://myhub.autodesk360.com/ue28f7901/g/shares/SH919a0QTf3c32634dcfab63700c6ef0ff4e

1 Like