Only started in March & have a 1 man system in a Ford transit Connect van with a Shurflo water pump wired to/working from the van battery. It was fine at first, doing small domestic jobs and driving off to the next, but now I'm working far longer it's starting to make the van battery go flat and I desperately need to connect another battery - but where do I start? I understand I need a leisure battery, but what size to be able to run 6-8 hrs non-stop and how do I connect it? Does the existing van alternator charge it up or what? Any advice would be really appreciated. Thanks!