Flipsky 75200 water cooling

EFOIL.builders Builds
#1

I am looking for any suggestions or feedback in implementing the watercooling feature of this VESC.

The aluminum block has two 8mm tunnels straight through it that have push in fittings that hold the plastic tube that Flipsky ships with it. The tube is very thin walled IMO and would easily kink so I will replace that component. Their design has the inflow into one of the passages returned and then travelling back through the the VESC to output on the same end it started. This is another design issue that seems flawed IMO as this would have water that has already absorbed some heat returning back through. It makes more sense to me to have the ambient temp water passing independently straight through the VESC so two inputs and two outputs. Those connections could possibly be implemented through two Y shaped fittings that will minimize the number of glands required.
I intend to use ram input only (no pump).

See photos for reference.

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#2

I think it will work as it is but even better with two y-connections, great idea.

You’re also right on the supplied tube, kinks easily, especially since the two ports are so close

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#3

I am going to use these little adapters I made 3d printed.

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okpTow - Jatem's style
#4

@Larsb
Thanks for the feedback. I was quite disappointed on the quality of the included tubing. From what I’ve seen this is a comparatively expensive VESC to put such low quality tubing on - perhaps supply chain issues caused this. However easy fix to change that to something else.
@windego has a creative solution and OKPTOW seems to have replacement fittings and tube that look higher quality in this thread

Have you actually implemented one of these as I would like to have a better understanding of what flow rate is required to keep the temp at a good level?

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#5

Sure, but i don’t know the flow rates, just that it doesn’t heat up for me.

#6

@Larsb
Thanks - encouraging to know that the watercooling is effective on this product.

#7

I use passive water cooling so the water is not pumped, it’s driven by the pressure created by the speed of the board. A small opening in the front of my clamp takes in water to the esc cooling.

I’m in sweden and water temperatures are always low so the ESC might get hotter if you’re in places like Thailand or the mediterranean (but from other users it seems to be no issue as well)

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#8

@Mantafoils would you remind us what your sea temperature is like in June July and August in UAE ? Do you still cool your ESC down with water on your 2023 range ?

#9

@Larsb
I am on a large fresh water lake in Canada so water temp here isn’t very “tropical” either😀

Can you provide me with a approximation on how fast the board need to be moving before you get water flow through the VESC?

Of course mast height, tube diameter etc comes into play just asking for your best guess.

#10

No idea, i need someone filming me to see that, outlet is on the bottom of the board. Might be a good idea to make it visible though, now that i think of it.

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#11

35 degree water in summer

#12

The energy capacity of the water is so high that running it back thru should be juuuuust fine. And yes ram water pressure should work fine as well. The quality of the water tube shouldn’t matter a whole lot either - it’s very low pressure water

#13

I don’t know the exact speed but I have passive water flow as my board starts to plane, this should be @ about 10 km/h (mast 75 cm, motor at about 10 cm, tube ID 8 mm)

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#14

@aemkei77
Thanks very helpful. :grinning:

You mention your inlet tube is 8mm inside dimension. Do you use a reducer to change to a piece of tube that fits into the 75200 water inlet fitting?

#15

I don’t have the original watercooling case but added a aluminum watercooler from ali to the 75200 alu case, thats why I use an ID8 tube.

With an ID6 tube you should get close to 60% of flow at the same speed

#16

It matters since the pressure is so low. If you get a kink on the tube there is no flow at all.

The supplied tube kinks really easily and the spring doesn’t help. In the end i changed to a more flexible tube which works a lot better. I took that from an old brake bleeder kit so don’t ask what it was :grinning_face_with_smiling_eyes:

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#17

@aemkei77

I’m interested in understanding the 60% value :grinning:

Not well versed in any of this so trying to learn as I go.

6 is 75% of 8 I think.

This has also got me considering using a larger diameter tube and then to a reducer before it goes into the 75200.

I’m wondering if a 10mm ID leading into the reducer would get water to the VESC at a slower initial speed?

#18

volume flow depends on cross section (r2pi of ID6 is 56,25% of that of ID8 - 60 was a rough estimate) and speed

I am by no way an expert in physics, but I think that initial speed of water flow depends more on the height water has to rise than on diameter of the tube (when within reasonable parameters)

but with a bigger tube you get more water through your esc

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#19

@aemkei77

Thanks for explaining the cross-sectional math - counts as todays learn something new every day goal. :grinning: