Going off the grid - Caravan Batteries and Solar Panels

Anybody can go on a caravan touring holiday and plug into an electric hook up on any uk caravan site or camp site. Holidays in France, I don't know about, because we haven't ventured there yet and I suspect they have a different plug or wattage.
Your caravan is your little home from home with all the mod cons, such as tv (sky or freeview) and laptop with wifi and hair dryer and electric kettle and electric blankets and toasters, you get the idea.
Which Caravan you have, will decide on how many sockets you have and how many appliances you could have on the go at any one time, ours only has 2 sockets, but we manage.

 By going off the electric and relying on your caravan leisure battery is a different type of holiday and can be more fun because it makes it a different experience. You need to consider when you can put on the lights or run the water pump to fill your sink. I think of it as like camping in a tent but a very luxurious tent with a fridge and a gas fire. By relying on your battery you need to switch your fridge over to run on gas and to use your gas fire instead of the electric one, although it's likely the same unit.
The caravan parts and accessories that will definitely make your holiday experience a better one are simple ones. A decent Leisure Battery is of course the best one to invest in. The more money you pay then the better the quality is a good adage to go by, but I often buy cheap if I can.
The most we have lasted is 3 nights and 4 days before the battery is showing as depleted.
For the future we intend on buying a solar panel which will keep the battery charging even on overcast days, but especially if we have sunny days.
I've read that you need at least a 100watts version and these can cost over £200, but I like the idea of charging the battery for free.

Wiring a solar panel into the battery compartment

Solar panel ready to go on the roof

 Here is a photo and link to a website that supplies what we are looking for.
The PV Logic range of portable, fold up solar panels is designed to be
highly transportable and quick and easy to set up and use.

 

Each portable solar panel has an integrated stand, a built-in charge controller and battery connectors. All you need to do is open up the panel, stand it up and connect it to your battery for instant power. Because the PV Logic foldup solar panels are self contained the usage is no limited to just caravan and motohomes, you can also use them with trailer tents and even general camping. The PV logic range of portable solar panels are supplied with a premium padded carry bag, easily stored in your caravan or motorhome and erected in minutes.

A couple that we know who go on lots of rallies use 2 batteries and their rooftop solar panel to charge 1 or the other depending which is in need of a top-up, with a simple switch. They use 1 battery for tv use only and the other for everything else and manage a week without any loss of power.
That's where I want to be.
Battery chargers have been a discussion point on many websites with many people waiting for Aldi or Lidl to have their special offer on and selling a very capable device for under £15. We would welcome any comments from people who know where to source the same cheap battery charger from the manufacturer, directly.
Please let me know in the comments below.