I want to power a motor with a battery, however the complication arises as I want to have two power sources and be able to switch between them. The context of this problem is for an electric vehicle. Sensing circuitry on the vehicle will measure speed and driver input and decide which of the two batteries to use under the conditions. i.e. when acceleration is needed the higher power battery is selected and power is drawn from that. When the vehicle is driving at slow speeds or at constant velocity the so called "cruising battery" will be switched to and used to power the motor. Both batteries will be at 48V and the motor power will be at a maximum of 5kW giving a maximum current of around 100A.
The above two circuits were suggested to me as possible ways of switching between the two batteries. I believe that a Schottky diode or capacitor of the correct rating can be found for fairly cheap however the main problem I seem to be facing is what type of switch to use and how to control this switch. On the circuits I have drawn a relay however am I right in thinking a contactor would be needed for a high power application such as this? In this case is it reasonable to control a contactor with a MOSFET as shown in the diagrams?
If anyone has any suggestions or advice for components that would be really useful, as well as suggestions for controlling the MOSFET/contactor. Using my current circuits the system would require 4 power sources, 2 for the motor, one for the contactor and one for the MOSFET!
Apologies for my inexperience or any unclear parts of my question.