Ive been struggling with my most recent build (as I have been with all of my previous builds lol). No one said it was easy!
I am using an Alien 80100 thanks to the post from @Mat. I followed the waterproofing steps outlined in that thread. Started out with a hobbyking 150A ESC submerged in dielectric oil that was circulated through a heat exchanger (an artifact from a previous build with a 6480 outrunner). The motor would spin up out of the water and behaved just fine. I went for my first test ride and once under load, almost immediately the motor failed. I pulled the board out of the water and when I gave it throttle the motor would just spin slowly for a few seconds before shutting off. All while sort of shuttering and chugging.
Thinking I may have blown the ESC since this larger motor pulls more current than probably safe for a 150A ESC, I purchased a 400A Flier Boat ESC. I hooked up the motor to the Flier and I get the exact same behavior. If I hook up another brushless motor to the ESC (my TP power inrunner for example) it seems to run just fine leading me to think it is a motor-related issue. I have tried playing with timing settings on the ESC with no improvement. Also, the motor spins freely/ normally by hand.
I next tested the motor with a multimeter. Resistance across all the windings is the same (0.6, 0.6 and 0.5 ohms). Ive read this isnt a very good test and that an LC meter is the better way to go, just dont have one. Interestingly, I also tested the resistance between the motor leads and the aluminum base plate of the motor. When I do this I measure a resistance of 3.4 Kohms. Pretty sure this indicates an abnormal short? There should be infinite resistance between any of the leads and the stator mount of the motor correct? If this is bad, do you think 3.4Kohms is low enough resistance to cause an issue? Furthermore, if so, any good ideas for how to find and fix this short?
Here is a video of whats going on: https://youtu.be/vm6GAyCyzbs
I am absolutely dying to get out on the water with this thing! This motor issue has been super frustrating so any advice would be very very appreciated! Thanks for the help!