So you got your old alternator rebuilt or you/mechanic found a new replacement?
I'd give the battery a proper overnight charge with a decent battery charger - you can't rely on the alternator to charge it 100%. 
 
 

yeah will def be doing that 2nite :) I've got a good charger so not a problem there :)
 
and yes I got it re-coed. The other one I ordered didn't fit! :|

ok mixed feelings atm - picked the car up, and it was showing 11.8v with the car running on the controller... definitely not the 13.8+ i was expecting! :\ the guys at the garage reckon the battery is fu-barred, but i had a second battery in parallel with this and still got the same voltage +/- 1v there was no distinct voltage difference between car on and car off... not sure if this could be a battery problem or not!.  
 
I've got a spare battery, so will try that bat instead, and charging my existing one now, but i honestly think there is another issue somewhere in the charging circuit! /cry!
 
at least i have a re-co'ed alternator - so that's something :)

ok further to the last post- swapped dad's battery into the car. still had exactly the same issue.  it's really weird, now it doesn't even do the warm thing at 14.4v then down to 12ish, it just starts straight to cold.  Definitely a ground problem :( 
 
I'm wondering if it can be a relay problem - the car momentarily went up to 14v then straight back down, really weird....
 
can anyone give me any more pointers on finding the ground problem? at the moment the only thing i can think of is to wiggle wires while looking at the volt meter? 
 
 

i've also checked all the fuses, including the big ones (swapped the heater and the alt fuse)
 
and ripped out the cold switch sensor.

Generally a bad alternator will also wreck the battery. At 11 volts at the battery is considered flat, do that a few times and you will kill of cells.
 
Having a 20 year old corolla finally go to heaven when the first alternator went on me i had it rewound and for ever gave me problems. Then i change it to a new one and changed the battery no issues

:\ this kinda stuff sux ass.
 
edit: i've got warranty on the rebuild, so will see how we go.
 

ok i'll be trying out voltage drop tests to test for s**ty grounds - 
http://www.autoshop101.com/forms/h8.pdf  - see page 14.
and then testing the relays too...
 
 

Even more basic than 101. Put a multimeter on the output of the alternator.
 
What Voltage is it < 14 volts throw it away
 
Dont even worry about grounds for now.
 
Thats what the guy who rewound your alternator will do when you complain.
 
Do that first then report back

oh of course, that's so simple! - from b term to chassis of alt?