Should i plan in Cooling? And if so, how?


i am planning my first USV for bathymetric surveys on lakes anywhere between 10 to 20ha at the moment and i think i figured everything out right now.

However, since i do not have any experience with this type of equipment yet, i am thinking about the heat radiation from the ESCs and if they would need any cooling.

Plan is, to build all the equipment into something like a pelicase or something similar, which by definition is watertight aswell as airtight. So it came into my mind, that temperature build up could possibly cause some problems.
The boat is designed to swim at slow speeds (somewhere around 1m/s) and the ESCs (2 of them) i’m thinking about will be 30A-40A without a fan.
So i guess, some simple airvents would not be sufficient enough.

I have been thinking about a fan on top of the case with a cover ontop to hold off any splash water. Now i’m unsure if just one fan pumping air in is enough. Or would it need another air outlet? Do you maybe have some ideas to make this more or less waterproof again?

Does anyone have some field experience here, which he would be willing to share? Maybe temperature isn’t a problem after all?

Thanks for your input :slight_smile:

P.s. here is my rudimentary 3d design. Just to provide a picture. The top part with all the electronics will be encased. Black would be the 2 batteries. Blue the esc. Red the pixhawk.

Thats a nice catamaran design. A 1:13 ration will help too.
I know that the ArduSub guys have their device in a mason jar under the sea for 4hrs and it is fine.

I guess the best option is to do some testing specific to your area. Have the setup do 24hrs of figure ‘driving’ in the hot sun and log the temp. One option could be to start at sunset and have the boat work over night.

Thank you. It’s basically a pretty simple pvc Pipe boat. But it should have a flotation capability around 9kg. The boat itself will probably be around 4-5kg. So that should give me plenty room to tinker around.

Edit: what do you mean exactly with a 1:13 ratio? Width:length or height:width?

I like your idea. I do have a cheap digital probe thermometer laying around to do an endurance run in the sun.
But i wanted to prevent overheating straight away and having to go for a swim :smiley:

I guess it won’t be so bad after all and i will keep the ecasement watertight for now. I could change it anytime when needed.

Building something similar for use in the southwest, did you ever experience any overheating problems?

On my boat Dumbo the original ESCs overheated and shut down when running in the summer; they had been fine during the school year. I think the clear lid on the enclosure made it get hotter inside than if I had painted the lid white.

My fix was to epoxy aluminum bar (1/8 x 2 inch, maybe 8 inches long) so it went through the bottom of the box. I zip tied the ESCs to these so the bars could conduct the heat outside without making a hole water could penetrate. The bottom of the bars were above the water when floating but airflow, spray, and waves kept them cool. I can’t find a picture showing the heat sinks.

I haven’t needed this in other boats so you may not either.

If your worried about overheating you should use a BLheli32 esc with telemetry, that way you can monitor the temperatures and most blheli ESCs will reduce power as they get too hot rather than just cut out.

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