Orion pack?
Why did'nt you say so.
Why thats the little bee's inside the batteries making honey.
Thats what makes them so sweet.
I'm not sure of all the technical hype but I think if your batteries have sat to long they will crystalize. And thats the buzzing noise?
Its waking up the cells so deffinitly be gentle with the charge rate.
Now as you stated its doing it with the 3300's. In that case take it to the local hobby shop. Unless they were bought used.
Be sure andlet us know what you find out?
I hate it when no one lets us know what became of a question like this.
Later.