intermittant heavy load on Alternator?

[Feelstranger]

So, back a while I mentioned to the list the I had an electrical meltdown that filled the interior with smoke while SO was driving.
Never found any evidence of meltation.
Messed with dash and alt circuit for a while trying to diagnose a low charge issue that may, or may not, have been related.   Eventually, it appeared to be working again with no particular help from me, as far as I know.
Interior is still in the garage, dash mostly uninstalled, and fire extinguisher on the pass seat!  What I do to drive this car!

To the question....
Driving it since then, I have experienced many incidents of low voltage on the voltmeter that typically go away eventually, or are gone at next start.

Recently, I realized that this intermittent low charge (voltmeter indicates as low as 12 V while running, sometimes more) was accompanied by occasional belt squeals which got me thinking that the low charge was actually a large load on the alt.  

Turning off lights, radio, seat heaters, etc, only helps a 
little.
Could I have a major short that is doing this?
So my plan (when I get the opportunity) is to start pulling fuses when the charge is low to see If I can isolate the problem circuit.

I'm open to other ideas, or BTDT.
Thanks
Nat