Mercedes C180 Elegance, charging battery problem.

Hi!

I've got Mercedes Benz c180 elegance 1995.

Problem is: "My battery doesn't charge automatically like ussual. I charge it manually. I take off the battery and charge it with that little machine in my house. I can drive it couple of minutes and if I catch some red lights, it turns off. Battery is empty always. So what can be a problem?"

Big greetings! Tnx