RE: What to use as a charger for 12V bettery?
Is it a 12v lead-acid car battery, or a small lead-acid or gel cell model battery ?
12v lead-acid car battery - need a proper car battery charger.
small model battery - either a standalone plug in charger designed for these batteries, or a multi charger that will charge nicads, nimhs, lipos & lead-acid hobby batteries.
If it is a small model battery, don't charge it with a normal car-battery type charger, as the charging current will be too high.