Before you start with the batteries, take a picture of the layout.
Note how the batteries are sitting, eg + / - !
The switch in back will only prevent the engine from starting.
Place some small plastic bags over the disconnected cable's.
The LABEL attached at the battery compartment with the layout is exactly
opposite as to how my starting batteries are connected.(No joke).
You will also loose some data, like the clock and date and so on.
One of my starting batteries started to out-gass massively at the 5 year mark.
The best deal on 2 new batteries was at NAPA, about $120 each, 18 months ago.
Siggy & Ursula.
2011 Newmar DSDP 4020 (no Tag, no DEF, 07 emission),
FTL XCR ,ISL 400,2015 Jeep Cherokee Limited, 4x4, V6, Active Drive II, BrakeBuddy