Hi DG,

I run brushless motors with matching ESC's and I have always water cooled them both.

My brushless motors are mounted on alloy water-cooled motor mounts and both are fed from a single water scoop pick-up.

This may well be a hang-up from the 1960's when all my r/c boats were powered by ic engines, but the water-cooled alloy motor mounts are a more recent thing that I have only been doing over the last few years.

I always buy water-cooled ESC, but I also have some water-cooled base plates that I bought for use with a non-water cooled ESC. I have not used these yet, but it looks like a nice simple idea, although heat rises and the efficiency of cooling the underside of the ESC may not be a perfect solution.

It is nice to be able to check the water flow from the outlet when the boat passes by so I can see that the cooling system is working well.

Mike C... Yes sorry about that. My motor will be a brushed MFA 800. The controller I have chosen is a Hobbywing Eagle 30A. I am planning to water cool it (if necessary) as its an easy addition onto this device.. There is minimal draw on the ESC, just the the Rx power.

I went for the Eagle 30A because I didn't want to have an automatic Brake or Reverse. This is the only ESC I could find with the capacity (just) for the MFA 800 and where I could jumper out the Brake and Reverse functions.

I appreciate any input other members offer as most are far more experienced boaters than I am!! I am really curious now to see how others 'Pick-up' the water feed or simply pump it with a small pump connected across the MFA or even with a 2nd ESC..
DG

You dont say what motor your using, is it Brushed or Brushless, I have mostly brushless motors in my boats, and fit waterproof speed controllers which have integral cooling system which you can attach cooling pipes too. I also fit a curved brass water pick up pipe through hull bottom just behind prop between prop and rudder so water is forced though cooling system and ejected through a short brass pipe msde to look like an exhaust. You can also get watercooled esc's for brushed systems but depends on how much power level your goin to need as to how much heat will be generated. Lower power/speed usually doesnt need cooling of esc's.
Mike C.🤗

Another (good) question with many opinions!

It depends on the design of the ESC. Obviously if the ESC has inlet/outlet connections for water then I suggest using water. As the ESC usually does not generate heat when not powering anything, a pair of force fed tubes through the hull might suffice. I run the tubes through the hull with the tips cut at a 45 deg in opposite directions. For higher performance motors a pump might be required. Also, does the ESC power other items that have signifipower power draw?

If the ESC has a heat sink, air flow via a decent size area is usually sufficient. Some ESC's have built in fans.

Best to check the spec for the ESC you have, see what others have done, or make after the fact changes.

Lew
Florida, USA

Sorry if this is off-thread but...
The fire hydrant at the bow was integrated into the cooling system. It ran in parallel with the esc cooling and there was a pump for the fire hose.

The electric pump was placed to suck water from the cooling water, which is why the scoop and exit for this were both under water.

She ran at a good impressive planing speed on 6 Ahr 'D' cells giving 12 volts. The esc was cold but you could not touch the D cells they were really hot.

I suppose delivering 150 Watts power and the associated heating of the battery pack was rather a lot! but she ran for about 40 minutes.

Roy

The only time I watercooled an esc was with an Electronize 15 Amp type. It was running 2 off Speed 600 motors and total current14 amps (measured under load).

I made a plate to fit the base of the unit with 2 off 5mm dia tubes soldered on and joined at the top by a neoprene tube.

I had a simple water scoop and a return for the water. The return was flush with the boat bottom and sloped away diagonally so the exit hole had a larger area then the scoop.

The scoop and exit part were cut from plastic oval section electric cable conduit about 20mm across.

The esc ran stone cold at 14 amps and the design leant itself to an easy flow of water for cooling.

So although this is all old hat regarding esc's you can run without a pump and you do not need much contact area for the cooling side.

For brushed motors the heat is around the brush area.

All the details were published in International Marine Modeller for the build of the Graupner Bremen 9. She is 40 inches long. The build photos I took were before digital photography so I found this one on the Internet.

Hope this helps,
Roy