You can do this by using the battery and then get a 12v usb Socket like the ones you can get for cars etc, we did this of another usb powered device outside, and also connected a solar battery charger to the battery, so far haven’t had to charge the battery, but now winternis her and less sun we will see
A dashcam powering kit connected to a 12VDC battery will work fine.
The V2 camera draws about 300mA @ 5VDC in day time. Somewhat more in Night mode when the IR illuminators light up.
If you’re powering a dash cam power kit (or other DC-to-DC converter) from a 12VDC battery, the current draw @ 12VDC will be about 140mA (daytime). You can do the math and figure out how long a big 12VDC battery would last, depending on hours of daylight, whether you have night mode enabled, ambient temperature, etc.
There are a lot of posts here by people looking at the possibility of using solar cells to keep a battery charged up. The cam consumes a couple of watts, so you’ll need a solar array of perhaps 8W or more to keep the cam running 7x24 (depending on your latitude, etc).
On Amazon, you’ll find after-market vendors selling outdoor enclosures for the V2 cam.
Or forget the battery, and run an exterior-rated cable to get 12VDC out to the camera location, then a dashcam kit to convert to 5VDC. RG-6/U coax is one option. I repurposed a CATV drop to get power out to the utility pole in front of my house.