Here's a little tip for those of you using 12 volt Gel batteries. Go see one of your local Alarm companies and ask them for a PC board from a "locked out" alarm panel. These are replaced boards that were code locked by another company and without the code, the alarm function isn't accessable. They have lots of them and when they are "locked" they are vitually useless as the cannot be reactivated for alarm purposes and will likely give them to you for free. However, they have a perfectly good, regulated 12 volt power supply/charger that will charge a 7 amp battery in about 14 hours or less. I use these all the time and have a few laying around. Cheap and effective.
Regards,
Keith