This happened to me for the first time yesterday. Wasnt really cold... Lower 40s. Remote started and drove to the store. Couple minutes into the drive the radio cuts out and the EVIC pops up the "battery saver mode" message which I'd never heard of. Checking online for this issue, finding it's happening a lot with 2019 HD Rams, but can't find a specific cause and fix for it... Causes seem to be all over the place. I bought this truck used three months ago with 19,000 miles on it. I'm at about 20,000 now. Haven't checked the batteries yet, but suspect the used car dealership may have put old batteries in the truck. I'm gonna check those and see what I've got, and go from there. Voltmeter indications seem to be fine, so I'm gonna keep an eye on it, make an an appointment with my dealership so they can take a look at it... See what happens. I'll post an update when I have one.