I bought a $19 dongle of amazon from china. The instructions are in English - sort of. I have an iphone but there are apps for android or ios. Took less than 5 minutes to set up.

I got to figure this out. The app read 13.7/13.9 the entire ride home. The voltmeter in the DIC read 12.6-12.9 for a while then jumped up to 14.9-15.2 for the second half of the ride. Voltage regulator? I may just swap the alternator to see if this helps.