I'm having some major problems with my Battery going flat ... When I got the battery the dude said I should probably get a larger battery (stock one is the small one) but he didn't have any spare terminal attachments to fit as he had run out. But he said it should be fine. So stupidly I left the boot light on in the car that night and the next afternoon the battery was flat. I got it charged back up to full and daily driving it seems fine. Although if I don't drive it for a few days its flat again. Now I jump start it and drive it for 30mins come home try it again in an hour and its flat again. Would this be the alternator not charging the battery enough ? Or something sucking juice from the battery and it being to small to hold enough charge ? I don't know whether i have a dud battery and can get another battery on warranty ?