Dashcam set up?

The answer is: "duct tape."

Attach the top of the phone to the wind shield and the bottom to the dash. The problem is getting the sticky adhere residue off the car and the phone. So you may want to try blue painter's masking tape because that blue tape does not leave a sticky mess as long as you don't leave the tape in place.

That said. You are going to have one huge editing task when yu get home as 99% of the footage will be boring. So be sure to take footage of people getting into and out of the car, many times and "b-roll" footage of close up id =hands or door handles, feet stepping and ignition key and faces of people looking out the windos and any other kinds of b-roll shots you can think of. So for this bring at least one more camera

Seriously, the duct tape idea works but the stuff is to good and is hard to remove. "Gaffer's tape" is sold at places that carter to pro photographers. It's black. But BLUE painter's tape sold at any hardware store works really well for unprovided iPhone mounting. Just do NOT leave the tape in place for more than about 12 hours.

 

I tried something similar and noticed that the recording stopped at around 45 minutes ( you could start another immediately ).

I believe it was a file size limit. I had plenty of space to record several more, each stopping around 45 minutes.

I have NOT tried it with the iPhone5S I have now ( does that thing have a 64bit chip? )

 

Way way easier to get a purpose specific device. It just really is.

Get a GoPro, a 3 inch round magnet from Harbor Freight, and make a mount for it. Put a lanyard on it, to slam in the door. Set the camera on the roof. Drive. Swap the RAM card when you need to. Set it in the car when you are not using it. Simple.