Way too complicated.
If both batteries are the same type, capacity and age - preferably
new - install fuses on each battery and run them in parallel to one
master switch. MUCH simpler, and you don't run one battery down before
switching to the other.
Have owned two gliders using this scheme with no problems. One with
two 12V 12A/H, one with two 12V 20A/H. The house runs on twelve 12V
220A/H sealed batteries in (4)series/(3)parallel configuration to give
48 Volts to the inverter. They seem quite happy after more than 6
years of service.
Jim

On Feb 26, 4:59 pm, AK wrote:

3) Does anyone have another solution for battery switching maybe
simpler one?