Adding batteries to an existing stack

[smoked_salt]

Hi
I already have a Mira BMS and 2 x batteries.

I was wondering the process for adding an extra two. Do I just need to flip the breaker on the BMS then disconnect the cables. Or should I turn the inverter off as well?

I read the manual but can't see anything about the power side of things.

On the plus side I've read the bit about the dip positions.

[smoked_salt]

Ignore my previous comment.
I found a section in the manual that says to turn off the inverter as well as the breaker on the BMS

[Fat Sting]

when you turn off the inverter (how actually) and BMS, is it safe to connect the new battery
What state of charge should the batteries be in?

cheers