The temperature in a car can get very high in summer when a car is parked, with the hottest place behind the rear-view mirror, which is exactly where best to mount a Dash Cam.
Now, not only is the environment hot, but the camera generates its own heat, such that it can be too hot to touch even on a cold day. Imagine how hot the camera gets on a sunny day inside a closed-up car. It can become so hot that there is a danger of the lens becoming distorted, so every Thinkware camera has a thermal shut off, when the conditions get too hot.
In the early days, Dash Cam’s used recharcheable batteries as a power backup, should the vehicle power fail on impact. Because the cameras were working 24/7, they would experience very high temperatures, and unfortunately rechargeable batteries don’t take kindly to being constantly charged at the same time as being subjected to high temperatures. As a result, there was a high failure rate. To solve this issue, Thinkware use super capacitors to provide the battery backup.
In summary, if you want a reliable camera with parking mode functionality, don’t get one with a rechargeable battery, many usually fail and just outside the warranty period.