I have an idea of using a 72V 3000W scooter motor as an underwater motor.
These motors are all over aliexpress, there seems to be several brands of the same motor. Examples are Yalu BM1109 and Kunray MY1020. However they all look the same.
The highest power version is rated for 3000W at 72V. This is a continuous rating (I think), so the peak power can be much higher. This is discussed on endless-sphere, the user coleasterling claims he’s running the motor in a toy car at 150 phase amps. That is a lot, three times the rated current (45A rated). Another user claimed 300A(!) peak in a go-kart.
To use the motor in water it needs a protective case of some sort, as it’s not waterproof. If it’s used under water however, it may be possible to double (or even triple) the continuous power rating.
The motor has a kv of around 70, which is good for direct drive. It has a quite large diameter at 107 mm and is also heavy at 5 kg, so it’s maybe not suitable for efoil. However I have plans on building an electric outboard motor with direct drive, and this motor is compelling. The construction seems solid and it’s sensored, which would allow for an advanced controller, e.g. a kellycontroller.
What do you think? Innovative or stupid, or maybe both?