Adding electric motor liquid cooling system

I'm in the process of changing our electric drive system from lead acid/brushed dc motor to a lithium battery and BLDC liquid cooled motor. Unfortunately slightly against the clock and while living aboard in lockdown with a couple of small kids, but hey ho...

Anyway, I'm looking for solutions for adding a cooling system in the next few weeks. The motor is an ME1616, we'll be drawing about 12-15kW and with 90%ish efficiency, losing 1.2-1.5kW of heat. Not a lot, but the motor will want a low inlet temperature to help the long term power handling, I'm aiming for 40-50 degrees at the inlet.

We don't have an existing ICE cooling system to reuse, and we can't come out of the water before we need to be cruising again. We're river based at the moment but will be back onto canals with debris and weeds at some point.

Skin tank is the obvious route to go, but I'm not sure how to size the system as we will be aiming for a low operating temperature for the cooling circuit, rather than 80-90 degrees of an ICE cooling syste,.

Open to any suggestions, advice, etc!

 

1500 watts of heat to dissipate.
That's the equivalent of a hairdryer.
Copper tubing with keel cooling, or just push outside water through.
Large, finned aluminum mounting brackets may work too, or both.

 

Heat transfer will pretty much scale with delta T compared to ambient, so if ambient temp is not greater than 10 degrees you will be looking at about half the stated cooling power for any ICE hardware.

I'd expect an old motorbike radiator would do this job nicely. Don't forget an expansion tank.