Towing 2018 Chevy Equinox

I had my own mechanic run some tests and he confirms that the battery is OK technically but the alternator is shot. However, we may be looking at two different situations - one is what is obviously a warranty issue (the alternator) and the other is that Chevy doesn't seem to know how to fix the battery going dead while towing issue. And yes we are in California so we do have the emissions test every two years. In our previous tow vehicle I once had to drive it 300 miles to make the computer testable. According to FMCA Chevy told them that they are adding the requirement of an in line charger as part of the tow wiring. However, when talking to customer support they deny that there's been any reported problems and their suggestion is to take it to the dealer to figure out. Putting in the battery disconnect switch seems like the best quick fix.