Re: [electricboats] Electric Motor for 40' Sailboat

Having designed electronic equipment for half a century, I have some experience in reliability. Powers needed for effective propulsion need water cooling. Losses in copper and iron are significant and removing this heat out of the motor area is difficult but made considerably easier with liquid cooling. Also lower operating temperatures means performance does not to be derated for hot weather. The controller, even with the very latest design will be dissipating closer to 1kw - think of that nice electric heater keeping you warm. It glows red hot . Electronic systems are most reliable around 25c and above 50c things start to get difficult to design in reliability.

Liquid cooling is a highly mature field of engineering. Salt water heat exchangers work exceptionally well if regularly maintained. However it might prove more reliable to run a heat exchanger like used on diesel engines with a radiator to transfer heat to air . Maybe both?

Best regards

Lee Eldridge

0427874796

On 11 Jun 2025, at 10:24, Matt Foley <matt@sunlightconversions.com> wrote:

 Air cooled is possible at 10-15kw as long as it's designed for it. Can even push it to 20kw with a lot of air exchange. Also keep in mind, I wouldn't do an air cooled 20kw, if you planned on actually using the full 20kw for hours on end. 

Matt Foley 

Sunlight Conversions

Perpetual Energy, LLC

201-914-0466

sunlightconversions.com

instagram.com/sunlightconversions/

youtube/sunlightconversions

ABYC Certified Marine 

Electrical Technician 

On Tuesday, June 10, 2025, 8:30 PM, Lee Eldridge <lee@vombatus.com.au> wrote:

have a look at freerchobby.

seems dodgy name but people I see on youtube are using their motors etc. outspinnermotors are highertorque lower speed

Best regards

Lee Eldridge

0427874796

On 11 Jun 2025, at 04:41, cammcnally10@outlook.com via groups.io <cammcnally10=outlook.com@groups.io> wrote:



Thanks Peter,

 

I would prefer an air-cooled system but did not see any engines listed on Thunderstruck that also met all my other requirements. I am still trying to figure out what specifications of an engine to value above others. I will definitely reach out to them as they have only received good reviews from this group.

 

-CM