Stupid Questions

Having had my first caravan for 2 weeks now I have realised that there are a lot of basic things that I don't know and that the man in my local caravan shop will quickly get fed up with me asking stupid questions so I'm going to ask them here and hope someone will take pity on me and reply. I will probably add to them as I discover more things I don't know.

1) Can I buy a battery charger that I can leave plugged into the mains and attached to the leisure battery in my van for long periods, i.e. when away for a week with mains hook up?

2) I have looked at the water inlet on my van and it appears to be a 1/2" pipe with what looks like a smaller than cigarette lighter 12V socket above it which I assume is the power supply for the water pump. All the water pumps I have looked at don't seem to come with connectors so how do I work out which one I need and how do I connect it.

Ok enough stupidity for now. more will no doubt follow!