Hi @yuvalm56 ,
If you are going to connect straight to the motherboard you may as well fix the charge port as it would involve nearly the same amount of work.
You say that it works when connected to the Home Charger and the Vehicle Charger but not when travelling in the vehicle due to movement, so it most probably is only a loose connection on the port itself.
Here is a [https://www.youtube.com/watch?v=vzHuRZaBqP8|video] that shows how to repair the port in your tablet. It is shown being replaced. In your case it might only have to be resoldered back onto the board.