System and lights on at night

Hello friends. 

I just noticed that whenever I drive my car at night.  After switching off the car, the system remains on ; the sorounding lights by the window and the lights by the gear remains on. 

But if I park during the day.  It stays off even at night. 

This only happens if I park my car at night.  

I believe  the lights drains my battery. So what I did last night was to remove the negative side of my battery. 

Please what's the final solution. 

Thanks