I have a Digital VM plugged into the Cigarette Lighter power socket, I don't recall actually taking a real close look at it, I will try and make a video recording though, snowing now.
but IIRC, some what close, it is still close to 12 volts or in the middle 11s
Don't hold me to that, but I will get a video as soon as I can.
I keep a Battery Tender on the truck, so it is always Floating at 13.3 to 13.6 before the Key is turn ON. had to change the batteries out a couple weeks ago, they were ruined when I bought the truck last June 2022... and I just suffered through until I finally got the Parasitic Draw Fixed..... then I bought new batteries...
I keep Battery Tenders on everything we own here,
EZ Go golf cart, old from the early '90s ( just put $1500 worth of new batteries in it
...... 1st time the Trojan I replaced batteries, and I bought it used in 2005 )
RV trailer
Zero Turn mower
'01 Suburban
'02 Excursion
'58 Kubota tractor
'09 Piaggio MP3 scooter
the old EZ Go batteries, I keep a very expensive trickle charger on them. I monitor water level close every 60 days, Distilled only.
Summit brand Charger --- gets plugged every time Cart is left unused, period......