Solar Panels work quietly while you have a nanna nap in the afternoon or while driving down the road to your next campsite.
They can be easily installed on the roof of your caravan or by using a folding solar panel you can stand it beside your van, tent or campervan. Although I have to say the best way to get good all day coverage is having a solar panel installed on the top of your caravan or mounted on roofracks on your vehicle.
They are then charging up your batteries all day not just when you stop for a cuppa or pull into a campsite. Why not take a look at the advantages and disadvantages of solar panels verses noisy and smelly generators