I agree with Hassan on the reliability and safety parts. EVs are not that simple that you slap a motor and batteries to covert the vehicle. There must be thermal management in order to cool the motor, batteries, and inverter.
Then there is battery management which manage the charging speed according to battery temperature in order to prolong battery life.
Then comes the most important part. Safety. The battery pack should be sealed, water proof, and impact resistant. It should be water proof to this level (check the video), otherwise it can catch fire
https://www.facebook.com/AutoPlayKH/videos/413183264908251
^ BTW, not even ICE vehicle can do this.
The point of writing all this is it's complex and require proper R&D. So leave to companies with proper engineers to avoid any loss.