Like someone posted before you can remove the aux from the equation if it fails. We do something similar on the wrangler JL’s with the aux battery. Even with a jump when the aux fails the Jeep will not run.
Aux Battery Delete-
Room for an H8 main battery which is the next mod.
- Pull fuse F52
- Remove negative jumper from aux to main
- Disconnect + cable from aux battery.
- Disconnect N3 cable from main bus. This is the aux + cable
- Remove aux battery
ESS still functions as normal but no longer uses the aux battery at shut off. Everything is running off the main battery at all times like most other major oems. No CELs or codes.