Cooling the ESC

Anyone else got an opinion on this? I have no idea where my foot placement will be. The Battery compartment will stick 60mm out of the board. It can withstand my weight, but stepping on it might make it difficult to ride?

I was thinking of placing the esc in a sealed aluminum box. The bottom of the box would be made from a heat sink with fins. The box would be mounted and sunk into the bottom of the board just ahead of, or just behind the mast with the fins facing downward.

Hi Max, I would try to find positions so that you neither step on ESC box or battery box while riding. I looks to me like right now that your front food would likely need to be on the battery box and the back foot might be on the ESC box. All depends on your wing setup of course, just judging from where I stand. My battery is in between the feet and I never feel the need to step close or on it.

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In my personal opinion, the position of your battery is perfect, if you look at the rest of efoils, the tendency is always to ride forward on the board due to the backward weigh. I think is better more weight near of the nose and can put the receiver without signal loss problems there too.
If you have a problem with the battery that is burning, probably you can save the rest of the electronic.

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I can stand on the ESC box. The gaps in front and behind it will get covered by a plate. Now I am not sure where to place things : ) I can still move the mast back and forth by 70mm.


I tried my new remote today so I took some pictures of the box



Looks very neat, thanks for sharing

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Looks great, but just be cautious those lipo packs expand (puff up) when they get hot, I have the same ones, and if you have ANYTHING near them with a point it could puncture the side of battery and cause an explosion. Looks like a tight fit in that battery box.


Is there a way to cool the esc/battery without water cooling? I want to build a sealed board so no leaks.
Using over kill esc (

I don’t think 300A is overkill if you want the electronics to run efficiently and cool. Anything smaller than 300A I feel will generate extra heat, waste energy, increase risk of fire/melting, and reduce the life of ESC. Drawing 80-135A is a ton of current and will get warm so watercooling is a must when ESC is stored in a sealed compartment. This ESC you show does not have water cooling and it will become an issue in my opinion.

What about using dynamic pressure as the water pump. Picture a pitot tube in the mast just above the motor pod, with a cooling tube that runs up to the parts that need cooling.

At low speeds (below take-off speed) the pressure required is very small since the water needs to be lifted only a few inches. At 11 mph, the pressure developed is about 1.8 psi or 50" of lift…plenty. Pressure increases as the square of velocity so cooling potential gets better with speed.

Pros: No moving parts, no electric power consumption, cooling increases with speed/power use.

Cons: plugging an issue?

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I feel using water pressure from in the duct or nozzle would work better as there is a lot more pressure. I also like the idea of the water shooting out of the board in an area you can see to be sure its working as it should.

The same thing with the flow, the more power you consume the more water is used for cooling which is great. I like that no electronics are required for this cooling method, its what I am doing.

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This creates many problems:
Clogs in Pipes
Erosion from salt

This method is used by many companies for colling motors etc… circulating water.
As always, users should flush and rinse efoil after use in salt water.
I do like the closed loop circulation system that Seadoo uses, but it requires a pump/electronics, though there are ways to do this without electronics…

What is your solution?

We have plenty of plumbing in our RV and its not that difficult. No issues whatsoever. Use good plastic tubes and those tube clips that you open with pliers. I would not recommend screw on hose clamps.

ya a boat ESC with water cooling is all of our solution… but you need water to cool it and that is what you said was the issue… how are water cooling it thats better than what we on the forum are doing?

I’m on this solution too, the less the better, on sea. But still I’ve to figure out how to run a plastic pipe from duct (Rice nozzle or whatever) all the way up to the board.
My mast clamp and propulsion system doesn’t have any room left and on the outside… doesn’t cause more drag?:thinking::thinking:
Do you have a photo or drawing?

Obviously, the best solution is inside the mast but if you don’t have room then maybe look at something flatter to shape to run up mast? If there is a section inside the mast that is separate, have tubing from duct into that area of the mast, and the mast section fills, then install nipple and hose coming out of mast near the board??

We have a design where the impeller nozzle that is 3d printed has the water inlet and area embedded within the 3D part and is accessible near the aluminum tube which is streamlined. But, we are planning on doing CNC aluminum parts with a lightly different design it looks like.

Hi, refugee from here, I was amazed to find the efoil branch, like many others I have been watching & enjoying @pacificmeister’s youtube channel.

Anyways yes esk8 loves the VESC (and it’s non copyrighted derivatives). In terms of cooling there is commercial options from a company called 3d Servitas based in Lithuania.

The owner is on ES -

His son is on esk8 builders and has worked with his father to design a case ystem for the Focbox which is probably the best price-point Vs quality VESC 4.12-based direct fet controller H/W out there right now, they have just completed a design and are making focbox controller boxes right now

No affliation, just a customer

So this Vesc thing is like an open source ESC? Like Arduino is for micro controllers?