WARNING: If you don't know anything about circuits leave because you will just be too confused.

So I guess most of guitarists have heard of this right? If not you basically make EMG 81 pickups run on a series of 2 9v batteries.

Here is a layout:

Well If you do this in a parralell circuit it stays at 9v, but increases battery life.

Now what I'm wondering is can you run a combination of both. So it would look like this (please excuse my horrible drawing):

Since parallel circuits don't increase voltage, but increase current, wouldn't this be a 18v with a very high current, which means a very VERY long battery life?