Hi.
Yes to make the batteries in parrallel do the following.
Connect battery 1 red pole to battery 3 red pole.
Connect battery 1 black pole to battery 3 black pole.
Connect battery 2 red pole to battery 4 red pole.
Connect battery 2 black pole to battery 4 black pole.
Your output Volts remain 24...
I do not agree that a blackout is imminent for the simple reason that the grid control at Simmerpan is adequately protected by automatic means.
This does not mean we can go down to stage 10 or 12 but the system is sufficiently protected against a total black out.
A total black out would take up...