Charge the battery

Moin, yesterday I wanted to leave the nugget after a long service life, but found that the starter battery did not have enough juice. So I simply connected the vehicle to the 230V line, assuming that the starter battery is charged, but that’s probably not the case, because this morning the starter still failed his service. If I assume that the starter battery is not charged on the wrong conditions, is it not? a another question on, what if I am connected to the 230V network at the campsite and listen to a lot of radio, can I not get away at some point? Small supplement: Can I clamp a charger directly to the starter battery without having to expand it? Greeting Gerd