Finally time to get liquid cooling installed. Spending most of August installing and ripping out some cooling structure as we try and figure out an optimum cooling configuration for the electric motor. I put together a long form post discussing the merits of cooling off your electric engine and controller.
I have to say that liquid cooling is necessary.
I had quite a few comments from various people about how they are dealing with heating. The motor doesn’t heat up as fast as the controller. The controller definitely does get hot.
I’d also like to say that I tested a whole bunch of speeds (wattages) and as it turns out I can run almost an hour without any cooling as long as I keep my engine in the 500 watt range. It seems that my behaviour of sailing into and out of the marina removed any real need for this, but longer high wind canal cruising necessitated this. I have a story here to tell you….
Aside, I am really loving this VRM from Victron Energy. This triggers the nerd in me. Here is the tracked graph now of my Motor controller. My sensor data gets picked up by the Cerbo GX and then transmitted over LTE all the way to Victron’s servers in Europe. The data is now tracked and as you can see I need cooling turned on. This graph here is the data newly being captured for review and analysis.
Interestingly, I have found that one of the phases runs hotter than the rest (U) I am not certain why, so I attached the thermal sensor to the (U) bolt on the controller. Now I have to figure out how to get a relay installed to trigger the on/off switch for the pumps and motor.
Hello Dan, Love your blogs and videos. I’m contemplating going electric and you’ve done a magnificent job explaining everything. Just a couple of questions that you may have answered but I can’t find. To isolate the electric motor from axial and radial loads it appears that you went for a shaft collar and not a set of bearings. Can you confirm?
Hi Charles, thanks for the feedback! I originally had a pillow block bearing and the motor shaft mounted above the propeller shaft. I used a couple of timing belt pulleys and a rubber timing belt. This was good, had a decent 1.92:1 ratio and but I wanted to test a direct drive.
For the direct drive (which I currently use) I flipped the motor and directly mounted it facing the prop shaft (so it looks like they are one shaft). The prop shaft has a bearing with 2 shaft lock collars on each side to keep the load from reaching the electric motor. I used a jaw coupler for each shaft and a spider gear (neoprene) between them. My motor shaft is 1″ and the propeller shaft 7/8″ so I made this from separate parts.
Because of the locking shaft couplers on the prop shaft, the load stays on the bearing, mounted to the large metal plate which is fixed to the original engine mounting bolts. This ensures that the electric motor doesn’t receive any loads from the prop and only turns the shaft. I have about 2 mm of flex/play in the coupler going from forward to reverse so it’s pretty tight and the spider gear takes up that slack.