you need to be more specific...alternator should charge at 13.8 - 14.2 volts...
if your alternator is not charging at that..make sure your battery is fully charged when you check this as a flat battery will show lower reading...could also be conections between alternator and battery..
however if it is a drain the most likely place is the head unit..where did you take your power supplys from??
any other info could help find your problem!!!