Battery problems

Lately I have been having problems where my battery has been totally draining. This is the second time this has happened so far. When I turn my key in the ignition it makes a clicking sound. The dash lights come on. Battery light and check engine lights are on. Last time this happened I jumped my car and it started right up. When I checked my twelve volt battery with a multi-meter, it read over thirty volts and slowly came down to seventeen volts in time. I took it to Autozone to have them check my battery, they said it was fine, but there was a problem with my alternator. Now, since my car is a hybrid, I know that it does not have the standard alternator but a belt alternator starter (BAS). Supposedly there is some sort of generator that replaces the average alternator? So then what could be the problem? It is a voltage regulator, right? Or could it be something more major? I am two and half hours away from a GM dealership and my car is dead once again. As I was driving, my check engine light came on and then two days later my battery died. I have been wanting to try to tear into it and fix this problem myself but I have found that there are no repair manuals for my car. This is pretty frustrating. And ideas?