We would recommend looking at the range of trickle chargers and battery maintainers by C-TEK - you can read our review of the latest NXT 5 model here - kit.honestjohn.co.uk/reviews/review-ctek-nxt-5/ Using a trickle charger when you car is not in use is an ideal way to counter battery drain on cars that suffer when not used regularly or only driven on short journeys. The C-TEK is an excellent choice as it can revive flat batteries and automatically maintains the optimum charge for long periods.