OK, I've finally seen the light and I'm switching to battery. I currently have one battery car that uses 18V Milwakee drill batteries. These are too big however to fit into a tank car or a coal hopper (without modification). So, I'm looking for an alternative before I invest in new batteries, chargers, and multiple battery cars. I've looked at the Aristocraft Li batteries, but they take overnight to charge. This won't work either. I like the Milwakee setup, but really want to avoid a box car on my tank unit train. What are others doing and what is the best overall battery system to work for multiple battery cars? Please help!