re: On board battery charger and new batteries not charging.

If the batteries sat on the shelf awhile they could have gotten low and built up a little sulfation. Normal chargers will continue pumping juice until the voltage gets above a certain mark, but if the battery has some sulfation it will have internal resistance and take awhile to get there. In the process it's very possible to boil out the water, so keep an eye on the level. Smart chargers will sense when a battery is in bad shape and will trickle charge in this state to repair. Not familiar with your charger but either situation would explain it going over a day with no green light.

Let them sit overnight on the charger and go from there. A voltmeter would tell you more of the story. Without that it's just guessing.