Dashcam turns off all the time

Hey, I’ve been installing a Dashcam in my Mazda 2 from 2017 for about 1.5 months. I used a hardware kit to prevent the battery from being unloaded in the parking mode of the Cam. It also ran perfectly for the first weeks. However, the camera went off and off all the time after about 3 weeks. After a few days it stayed out. When it went on again, it quickly went off again and stayed it too. My car battery is therefore also in use for 7 years. What could the problem be? The battery has never actually made a problem and I would like to exchange the battery for almost 150€ only on suspicion. Thank you! I’d like to thank you very much.