mini 0826 problem not recodring

Hi I bought the camera a few months ago. I noticed that in parking mode, it records for 8 hours roughly, and then it stops. I tried to change the voltage settings and time settings. I also formatted the camera multiple times. No luck. I have a new Mercedes and it is impossible that the battery...

I have mini 0826 from gearbeast (without 8gb internal memory) and problem it always doesnt record automatically when i turn car on and drive it. Sometimes it does. so its intermittent problem. When not recording it switches off as I beleive its in standby mode.. I am using a 32GB Sandisk Ultra...