After watching tons of videos on Youtube, reading reviews.. I will give you the summary. Done this for 2 of my cars and plan on doing it to my third. In todays world you gotta have dashcams to help protect yourself from the he-said she-said during car wrecks. As I told my wife hopefully we won't have a wreck, but peace of mind and a setup where you can set it and forget it. Automatic, doesn't drain your car battery, switches from normal mode to parking mode, etc...
This is the way to go. You want this Blackboxmycar "BBMC" Powercell 8 battery paired with your camera. Side note my dash cam recommendation is VIOFO A139 PRO 4k (I went with 3-channel version). BBMC makes it easy to order the USB-C hardwiring kit pre-spliced. Simply install your dash cam and put your powercell where you want it, run your cables. They include the Add-a-fuse for you to easily pair Positive with IGN in fuse box (black/negative pairs to metal nut nearby on chassis.. You could use the 12V cig adapter, but its clean having wires tucked away and out of site. I had a little side area I never use next to middle console in truck where I tucked the battery. In other car I put battery under carseat.
Make sure to tell BBMC after you order it that you're ok waiving signature requirement because the normal method is they require signature confirmation.
Overall 5 stars.