Why not just turning off the
MPPT controllers, battery chargers,
alternator regulators etc. instead of disconnecting everything?
For the battery bank, turn off the main battery switch first, then disconnect and remove the series jumpers. Now disconnect the main positive cable and wrap it’s terminal with tape, then put to the side. Next do the same for the negative cable.
If there are any temperature or voltage sensors etc., remove them all so you have battery tops ready for
cleaning.
I like to use the cleaner from CRC and rinse with clean fresh
water. Don’t forget the protector during reassembly. You can use NoOxId or dielectric grease etc.