12vdc and 24vdc

Can someone look this over and tell me if I got it right?
I have a few items I want to run and they are 24vdc. They wont be running all the time and I don't want to have to deal with the dueling battery syndrome.

Thank you ahead of time for any help.

Or do I need two solenoids hooked up to the same switch like so?

In order to obtain 24V, the AUX batteries need to have a series connection. The negative of one battery must connect to the positive of the other. The diagram shows the negatives of all the batteries being common. When the solenoid (connections shown by yellow wires) operates, bad things will happen to AUX 1 battery, and associated wiring. The ground connection to AUX 2 battery needs to be isolated.
The charger may also need to share this isolated connection, if the negatives of the charger are common.

If I isolate Aux 2 battery ground like so, then how would the battery get charged from the output of the dual battery isolator?

Also, it looks like I wouldn't be able to pull the 12vdc off of Aux two without isolating and running separate grounds.

Thank you again for the help with this.

The system would need to be setup with relays isolating the batteries. Two modes of operation, charge and discharge. Charge mode allows charging by a 12 volt (nominal) source. Discharge isolates one of the batteries and connects it in series to the other.

It can be done with a rotary cam switch like so?

I had to fix the Aux 1 and Aux 2 Neg posts in the drawing.