Quick question...

[HappyOne]

All other things being equal, which tends to get hotter the brushless motor or esc?

Assume that both are properly water cooled.

Thanks.

[Raydee]

That is a good question...mine usually come out of the water pretty close to the same temps.

[sailr]

It is commonly accepted that the ESC gets hotter so you run the cooling water through it first and then through the motor.

[Chilli]

My Etti 150 / Feigao boat, they are about the same.
On the Etti 150 / Neu set up, the Neu runs a bit cooler.

[Fluid]

There is NO general answer to the OP's question. It depends heavily on the motor and the ESC, and the setup. For example, if you are running the ESC close to its maximum rated amperage with a large format motor - a Feiago XL for example - the ESC will be hotter. If the ESC has a high amp capacity and the motor is relatively small - like a Feiago S - the motor will get hotter.

The ESC is cooled first because the water is colder fresh out of the pond, hense it will do a better job of reducing the ESC's temperature - simple thermodynamics. Because the ESC is deemed more 'fragile', it needs the cooling the most. Too, the cooling on all ESCs is pretty inefficient so the water coming out is not very warm - it works fine to cool the motor.



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[Simon.O.]

I will go with Jay on this one.
There is no magic answer.

I can run a 200A esc on my 8S motors and cook the motor but the esc never got warm.
I can run a 60A esc on a 7XL with a 440 and what happened ?? It thermaled but survived to see another day. I managed to kill it another way.

The general plan is to match the esc to the motor allowing a fair bit of "fat"on the esc side.
I work out what the motor "may" draw and get an esc that will provide 25%(min) more.

e.g my 12S can pull about 100A (that may kill it) so I get a esc that can go to 125A Easy !!

For me being a solo boater, and a cheap bugger to boot, I use the gear from HK and a bit from here at OSE.

Do the maths and work out what you need. There is no need to blow expensive bits.

I can help and so can many others here.

[Fluid]

I will go with Jay on this one...

So near and yet so far. I'm in Melbourne at the moment......





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[racerr73]

Not coming to Brisbane by any chance are you Jay while you are in Australia?

[sailr]

Good comments. All very valid. I always over-amp on the esc side. If you 'think' 100A will do, go to 125A or 150A on the esc.

[HappyOne]

Thanks. The reason I asked is that I just got a DX3S and it supports telemetry for receiver battery, temperature and rpm. I was trying to figure out whether to put the temperature probe on the motor or the ESC. Both boats that I will set up this way have lots of headroom in the ESC so I will install the probe on the motor.

Thanks for everyone's help.

[Fluid]

Not coming to Brisbane by any chance are you Jay while you are in Australia?

There is a slight chance I may go for a day but time will be very tight. I'll let you know if I do come over.




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[racerr73]

Ok then no worries.