After having experienced some problems with the battery going flat while not using the car for a few days (more like 2 weeks), I decided I've had enough of calling out MB (twice so far). Anyway, bought a "proper" MB branded trickle charger from local dealer who told me "just plug it in and you can leave it for long periods of time". Great. Just reading the manual.... get a bit worried about the ventilation issues. Car won't fit in garage but have a long enough leads to leave the trickle charger in the boot while away. Concern is of course, there will not be any ventilation to speak about in a closed boot.... lead in not quite long enough to leave charger in garage. Any risks with this or am I just simply paranoid? Thanks.