I would like to replace the battery in this recently acquired 2009 ST1300PA. It appears that they retrofitted a larger capacity battery (oddysey PC545). It was installed on it's side which I read is Ok, but is really crammed in there and very difficult to remove and install. I would like to install a light weight Lithium type battery if possible. Does anyone know if the the police model has an upgraded alternator or anything that might pose a problem retrofitting a smaller battery? I guess I would also have to install anything I find on its side due to the small footprint (3.33"x5.0") of the battery tray. Any help or guidance would be extremely appreciated, thanks.