Gin,
I too have replaced batteries in my S1 2002. I did this when starting resulted in a click on the 1st attempt each time I fired it up. The first battery replacement solved the problem completely for just over a year. This year I went for the fix Millers Commercials recommends and had them replace the starter motor with a quality Bosch unit. So far this has been perfect, a much more vigourous starting and fires everytime. Even when the car is not on a trickle charger.
